QT60161B-AS - Quantum Research Group

LQQT60161B

16 K

QMatrix

™

EYPANEL

ENSOR

Advanced second generation QMatrix controller

16 touch keys through any dielectric

100% autocal for life - no adjustments required

SPI Slave or Master/Slave interface to a host controller

Parallel scan interface for electromechanical compatibility

Keys individually adjustable for sensitivity, response time,

and many other critical parameters

Sleep mode with wake pin

Synchronous noise suppression

Mix and match key sizes & shapes in one panel

Adjacent key suppression feature

Panel thicknesses to 5 cm or more

Low overhead communications protocol

44-pin TQFP package

APPLICATIONS -



Automotive panels



Machine tools



ATM machines



Touch-screens



Appliance controls



Outdoor keypads

Security keypanels



Industrial keyboards

The QT60161B digital charge-transfer (“QT”) QMatrix™ IC is designed to detect human touch on up 16 keys when used in

conjunction with a scanned, passive X-Y matrix. It will project the keys through almost any dielectric, e.g. glass, plastic, stone,

ceramic, and even wood, up to thicknesses of 5 cm or more. The touch areas are defined as simple 2-part interdigitated

electrodes of conductive material, like copper or screened silver or carbon deposited on the rear of a control panel. Key sizes,

shapes and placement are almost entirely arbitrary; sizes and shapes of keys can be mixed within a single panel of keys and can

vary by a factor of 20:1 in surface area. The sensitivity of each key can be set individually via simple functions over the SPI or

UART port, for example via Quantum’s QmBtn program, or from a host microcontroller. Key setups are stored in an onboard

eeprom and do not need to be reloaded with each powerup.

The device is designed specifically for appliances, electronic kiosks, security panels, portable instruments, machine tools, or

similar products that are subject to environmental influences or even vandalism. It can permit the construction of 100% sealed,

watertight control panels that are immune to humidity, temperature, dirt accumulation, or the physical deterioration of the panel

surface from abrasion, chemicals, or abuse. To this end the device contains Quantum-pioneered adaptive auto self-calibration,

drift compensation, and digital filtering algorithms that make the sensing function robust and survivable.

The part can scan matrix touch keys over LCD panels or other displays when used with clear ITO electrodes arranged in a matrix.

It does not require 'chip on glass' or other exotic fabrication techniques, thus allowing the OEM to source the matrix from multiple

vendors. Materials such as such common PCB materials or flex circuits can be used.

External circuitry consists of a resonator and a few capacitors and resistors, all of which can fit into a footprint of less than 6 sq. cm

(1 sq. in). Control and data transfer is via either a SPI or UART port; a parallel scan port provides backwards compatibility with

scanned electromechanical keys.

The QT60161B makes use of an important new variant of charge-transfer sensing, transverse charge-transfer, in a matrix format

that minimizes the number of required scan lines. Unlike some older technologies it does not require one sensing IC per key.

The QT60161B is identical to earlier QT60161 in all respects except that the device exhibits lower signal noise. This

device replaces QT60161 parts directly. After December 2003 the QT60161 will no longer be sold.

Pat Pend. R1.03/04.03

QT60161B-AS-40

C to +105

TQFP Part NumberT

AVAILABLE OPTIONS

VREF

DRDY

LED

Vss

Vdd

CS0A

CS0B

CS1A

CS1B

SMP

X0OPA

X1OPB

Vdd

Vss

XS0

XS1

XS2

XS3

MOSI

MISO

SCK

RST

Vdd

Vss

XTO

XTI

WS YS0

YS1

YS2

YS3

AVdd

AGnd

Aref

CS3B

CS3A

CS2B

CS2A1

11 23

44 43 42 41 40 39 38 37 36 34

12 13 14 22

19 2018

1615

QT60161B

TQFP-44

y 0x79 - Column Keys Scope

...........................

x 0x78 - Row Keys Scope

.............................

S 0x53 - All Keys Scope

..............................

s 0x73 - Specific Key Scope

...........................

185.2 Scope Commands

..............................

p 0x70 - Put Command

..............................

g 0x67 - Get Command

..............................

175.1 Put / Get Direction Commands

.....................

5 Commands & Functions

.............................

164.8 Eeprom Corruption

..............................

154.7 Parallel Scan Port

...............................

154.6 Sensor Echo and Data Response

..................

144.5 UART Interface

.................................

134.4 SPI Master-Slave Mode

..........................

124.3 SPI Slave-Only Mode

............................

124.2 SPI Port Specifications

...........................

114.1 Serial Protocol Overview

..........................

4 Communications Interfaces

..........................

113.18 ESD / Noise Considerations

......................

113.17 Power Supply & PCB Layout

.....................

113.16 Oscilloscope Sync

..............................

103.15 LED / Alert Output

..............................

93.14 Sleep_Wake / Noise Sync Pin (WS)

.................

93.13 Startup / Calibration Times

.........................

93.12 Oscillator

.......................................

93.11 Reset Input

.....................................

93.10 Water Film Suppression

...........................

93.9 Sample Capacitors

................................

93.8 Burst Spacing

....................................

93.7 Intra-Burst Spacing

................................

83.6 Burst Acquisition Duration

..........................

83.5 Burst Length & Sensitivity

...........................

3.4.2 Noise Coupling Into Y Lines

............................

3.4.1 RFI From Y Lines

..................................

83.4 'Y' Gate Drives

....................................

3.3.2 Noise Coupling Into X lines

............................

3.3.1 RFI From X Lines

..................................

83.3 'X' Electrode Drives

................................

73.2 Signal Path

......................................

73.1 Matrix Scan Sequence

.............................

3 Circuit Operation

.....................................

72.11 Device Status & Reporting

.........................

72.10 Full Recalibration

.................................

62.9 Adjacent Key Suppression (‘AKS’)

....................

62.8 Reference Guardbanding

...........................

62.7 Positive Recalibration Delay

.........................

62.6 Detection Integrator

................................

62.5 Negative Recalibration Delay

........................

52.4 Drift Compensation

................................

52.3 Hysteresis

.......................................

52.2 Positive Threshold

.................................

52.1 Negative Threshold

................................

2 Signal Processing

....................................

41.3 Communications

..................................

41.2 Circuit Overview

..................................

41.1 Field Flows

.......................................

1 Overview

............................................

8 Index

.............................................

337.2 Marking

.......................................

337.1 Dimensions

....................................

7 Mechanical

........................................

326.5 Maximum Drdy Response Delays

..................

316.4 Protocol Timing

.................................

316.3 DC Specifications

...............................

316.2 Recommended operating conditions

................

316.1 Absolute Maximum Specifications

..................

6 Electrical Specifications

............................

305.8 Erratta / Notes

.................................

305.7 Timing Limitations

..............................

275.6 Function Summary Table

.........................

^W 0x17 - Noise Sync

...............................

^R 0x12 - Oscilloscope Sync

...........................

^Q 0x11 - Data Rate Selection

..........................

Z 0x5A - Enter Sleep

................................

W 0x57 - Return Part Signature

.........................

V 0x56 - Return Part Version

...........................

r 0x72 - Reset Device

...............................

l 0x6C - Return Last Command Character

...................

b 0x62 - Recalibrate Keys

.............................

L 0x4C - Lock Reference Levels

.........................

6 0x36 - Eeprom Checksum

...........................

245.5 Supervisory / System Functions

....................

^P 0x10 - Adjacent Key Suppression (‘AKS’)

..................

^O 0x0F - Negative Reference Error Band

...................

^N 0x0E - Positive Reference Error Band

....................

^M 0x0D - Intra-Burst Pulse Spacing

.......................

^L 0x0C - Negative Recalibration Delay

.....................

^K 0x0B - Positive Recalibration Delay

.....................

^J 0x0A - Negative Detect Integrator Limit

...................

^I 0x09 - Positive Drift Compensation Rate

..................

^H 0x08 - Negative Drift Compensation Rate5

.................

^G 0x07 - Burst Spacing

..............................

^F 0x06 - Burst Length

...............................

^D 0x04 - Positive Threshold Hysteresis

.....................

^C 0x03 - Negative Threshold Hysteresis

....................

^B 0x02 - Positive Detect Threshold

.......................

^A 0x01 - Negative Detect Threshold

.......................

215.4 Setup Commands

..............................

k 0x6B - Reporting of First Touched Key

....................

E 0x45 - Error Codes for Group

.........................

e 0x65 - Error Code for Selected Key

......................

% 0x25 - Detect Integrator Counts for Group

.................

" 0x22 - Reference Levels for Group

......................

! 0x21 - Delta Signals for Group

.........................

<sp> 0x20 - Signal Levels for Group

.......................

7 0x37 - General Device Status

..........................

6 0x36 - Eeprom Checksum

...........................

5 0x35 - Detection Integrator Counts

......................

2 0x32 - Reference Value

.............................

1 0x31 - Delta Signal for Single Key

.......................

0 0x30 - Signal for Single Key

..........................

185.3 Status Commands

...............................

©Quantum Research Group Ltd.

www.qprox.com QT60161B / R1.03

Contents

Table 1.1 Device Pin Lis

Slave select for SPI direction control; active lowI/O ODSS44

Oscilloscope sync outputO PPSO43

Vref input for conversion referenceIVref42

Data ready output for Slave SPI mode; active lowO ODDRDY41

Active low LED status drive / Activity indicatorO PPLED40

GroundPwrVss39

+5 supplyPwrVdd38

Cs0 control AI/O PPCS0A37

Cs0 control BI/O PPCS0B36

Cs1 control AI/O PPCS1A35

Cs1 control BI/O PPCS1B34

Cs2 control AI/O PPCS2A33

Cs2 control BI/O PPCS2B32

Cs3 control AI/O PPCS3A31

Cs3 control BI/O PPCS3B30

+5 supply for analog sectionsPwrAref29

Analog groundPwrAGnd28

+5 supply for analog sectionsPwrAVdd27

YS3 Scan output lineO PPYS326

YS2 Scan output lineO PPYS225

YS1 Scan output lineO PPYS124

YS0 Scan output lineO PPYS023

XS3 Scan input lineIXS322

XS2 Scan input lineIXS221

XS1 Scan input lineIXS120

XS0 Scan input lineIXS019

GroundPwrVss18

+5V supplyPwrVdd17

X3 Drive matrix scanO PPX316

X2 Drive matrix scanO PPX215

X1 Drive matrix scan / Communications option B inputI/O PPX1OPB14

X0 Drive matrix scan / Communications option A inputI/O PPX0OPA13

Sample output controlO PPSMP12

Wake from Sleep / Sync to noise sourceIWS11

UART transmit outputO PPTX10

UART receive inputIRX9

Oscillator drive input. Connect to resonator or crystal, or external clock source.IXTI8

Oscillator drive output. Connect to resonator or crystal.plyO PPXTO7

GroundPwrVss6

+5V supplyPwrVdd5

Reset input, active low resetIRST4

SPI Clock. In Master mode is an output; in Slave mode is an inputI/O PPSCK3

Master-In / Slave Out SPI line. Not used in Master/Slave SPI mode.

In Slave mode outputs data to host (out only).

I/O PPMISO2

Master-Out / Slave In SPI line. In Master/Slave SPI mode is used for both communication directions.

In Slave SPI mode is the data input (in only).

I/O PPMOSI1

DescriptionTypeNamePin

I/O: I = Input

O = Output

Pwr = Power pin

I/O = Bidirectional line

PP = Push Pull output drive

OD = Open drain output drive

©Quantum Research Group Ltd.

iii

www.qprox.com QT60161B / R1.03

1 Overview

QMatrix devices are digital burst mode charge-transfer (QT)

sensors designed specifically for matrix geometry touch

controls; they include all signal processing functions

necessary to provide stable sensing under a wide variety of

changing conditions. Only a few low cost external parts are

required for operation. The entire circuit can be built in under

6 square centimeters of PCB area.

The device has a wide dynamic range that allows for a wide

variety of key sizes and shapes to be mixed together in a

single touch panel. These features permit new types of

keypad features such as touch-sliders, back-illuminated keys,

and complex warped panels.

The devices use an SPI interface running at up to 3MHz rates

to allow key data to be extracted and to permit individual key

parameter setup, or, a UART port which can run at rates to

57.6 Kbaud. The serial interface protocol uses simple

commands; the command structure is designed to minimize

the amount of data traffic while maximizing the amount of

information conveyed.

In addition to normal operating and

setup functions the device can also

report back actual signal strengths

and error codes over the serial

interfaces.

QmBtn software for the PC can be

used to program the IC as well as

read back key status and signal

levels in real time.

A parallel scan port is also provided

that can be used to directly replace

membrane type keypads.

QMatrix technology employs

transverse charge-transfer ('QT')

sensing, a new technology that

senses the changes in an electrical

charge forced across an electrode

set.

1.1 Field Flows

Figure 1-1 shows how charge is

transferred across an electrode set

to permeate the overlying panel

material; this charge flow exhibits a

high dQ/dt during the edge

transitions of the X drive pulse. The

charge driven by the X electrode is partly received onto the

corresponding Y electrode which is then processed. The part

uses 4 'X' edge-driven rows and 4 'Y' sense columns to sense

up to 16 keys.

The charge flows are absorbed by the touch of a human

finger (Figure 1-1) resulting in a decrease in coupling from X

to Y. Thus, received signals decrease or go negative with

respect to the reference level during a touch.

As shown in Figure 1-3, water films cause the coupled fields

to increase slightly, making them easy to distinguish from

touch.

1.2 Circuit Overview

A basic circuit diagram is shown in Figure 1-5. The ‘X’ drives

are sequentially pulsed in groupings of bursts. At the

intersection of each ‘X’ and ‘Y’ line in the matrix itself, where

a key is desired, should be an interdigitated electrode set

similar to those shown in Figure 1-4. See Quantum App Note

AN-KD01, or consult Quantum for application assistance.

The device uses fixed external capacitors to acquire charge

from the matrix during a burst of charge-transfer cycles; the

burst length can be varied to permit digitally variable key

signal gains. The charge is converted to digital using a

single-slope conversion process.

Burst mode operation permits the

use of a passive matrix, reduces RF

emissions, and provides excellent

response times.

Refer to Section 3 for more details

on circuit operation.

1.3 Communications

The device uses two variants of SPI

communications, Slave-only and

Master-Slave, a UART interface,

plus a parallel scan interface. Over

the serial interfaces are used a

command and data transfer

structure designed for high levels of

flexibility using minimal numbers of

bytes. For more information see

Sections 4 and 5.

The parallel scan port permits the

replacement of electromechanical

keypads that would be scanned by

a microcontroller; the scan interface

mimics an electromechanical

keyboard’s response.

©Quantum Research Group Ltd.

www.qprox.com QT60161B / R1.03

Figure 1-2 Field Flows When Touched

Figure 1-3 Fields With a Conductive Film

overlying panel

element

Figure 1-4 Sample Electrode Geometries

PARALLEL LINES SERPENTINE SPIRAL

Figure 1-1 Field flow between X and Y elements

overlying panel

element

elem ent

2 Signal Processing

The device calibrates and processes signals using a number

of algorithms specifically designed to provide for high

survivability in the face of adverse environmental challenges.

The QT60161B provides a large number of processing

options which can be user-selected to implement very

flexible, robust keypanel solutions.

2.1 Negative Threshold

See also Command ^R, page 26

The ‘SO’ pin can output an oscilloscope sync signal which is

a positive pulse that brackets the burst of a selected key. This

feature is controlled by the ^R command. More than one burst

can output a sync pulse, for example if the scope of the

command when set is a row or column, or is all keys. The ^R

command is volatile and does not survive a reset or power

down.

This feature is invaluable for diagnostics; without it, observing

signals clearly on an oscilloscope for a particular burst is

nearly impossible.

This function is supported in QmBtn PC software via a

checkbox.

3.17 Power Supply & PCB Layout

Vdd should be 5.0 volts +/- 5%. This can be provided by a

common 78L05 3-terminal regulator. LDO type regulators are

often fine but can suffer from poor transient load response

which may cause erratic signal behavior.

If the power supply is shared with another electronic system,

care should be taken to assure that the supply is free of

low-level spikes, sags, and surges which can adversely affect

the circuit. The devices can track slow changes in Vcc

depending on the settings of drift compensation, but signals

can be adversely affected by rapid voltage steps and impulse

noise on the supply rail.

Supply bypass capacitors of 0.1uF to a ground plane should

be used near every supply pin of every active component in

the circuit.

PCB layout: The PCB layout should incorporate a ground

plane under the entire circuit; this is easily possible with a

2-layer design. The ground plane should be broken up as

little as possible. Internal nodes of the circuit can be quite

sensitive to external noise and the circuit should be kept

away from stray magnetic and electric fields, for example

those emanating from mains power components such as

transformers and power capacitors. If proximity to such

components is unavoidable, an electrostatic shield may be

required.

The use of the Sync feature (Section 3.14) can be invaluable

in reducing these types of noise sources, but only up to a

point.

3.18 ESD / Noise Considerations

In general the QT60161B will be well protected from static

discharge during use by the overlying panel. However, even

with a dielectric panel transients currents can still flow into

scan lines via induction or in extreme cases, dielectric

breakdown. Porous or cracked materials may allow a spark to

tunnel through the panel. In all cases, testing is required to

reveal any potential problems. The IC has diode protected

pins which can absorb and protect the device from most

induced discharges, up to 5mA.

The X lines are not usually at risk during operation, since they

are low-resistance output drives. Diode clamps can be used

on the X and Y matrix lines if desired. The diodes should be

high speed / high current types such as BAV99 dual diodes,

connected from Vdd to Vss with the diode junction connected

to the matrix pin. Diode arrays can also be used.

Capacitors placed on the X and Y matrix lines can also help

to a limited degree by absorbing ESD transients and lowering

induced voltages. Values up to 100pF on the X lines and

22pF on the Y lines can be used.

The circuit can be further protected by inserting series

resistors into the X and/or Y lines to limit peak transient

current. RC networks as shown in Figures 4-6 and 4-7 can

provide enhanced protection against ESD while also limiting

the effects of external EMI should this be a problem.

External field interference can occur in some cases; these

problems are highly dependent on the interfering frequency

and the manner of coupling into the circuit. PCB layout

(Section 3.17) and external wiring should be carefully

designed to reduce the probability of these effects occurring.

SPI / UART data noise: In some applications it is necessary

to have the host MCU at a distance from the sensor, perhaps

with the interface coupled via ribbon cable. The SPI link is

particularly vulnerable to noise injection on these lines;

corrupted or false commands can be induced from transients

on the power supply or ground wiring. Bypass capacitors and

series resistors can be used to prevent these effects as

shown in Figures 4-6 and 4-7.

4 Communications Interfaces

The QT60161B uses parallel, UART, and SPI interfaces to

communicate with a host MCU. The serial interfaces use a

protocol described in Section 5. Only one interface can be

used at a time; the interface type is selected by

resistor-coupled jumpers connected to pins X0OPA (pin 13)

and X0OPB (pin 14) shown in Table 4-1. See also Figure 3-2.

Further specific information on each interface type is

contained in the following sections:

SPI Slave-Only Mode: Section 4.3

SPI Master-Slave Mode:Section 4.4

UART Interface:Section 4.5

Parallel Interface:Section 4.7

4.1 Serial Protocol Overview

The SPI and UART interface protocols are based entirely on

polled data transmission, that is, the part will not send data to

the host of its own volition but will do so only in response to

specific commands from a host.

©Quantum Research Group Ltd.

www.qprox.com QT60161B / R1.03

Run-time data responses, such as key detection or error

information, requires simple single-byte functions to evoke a

response from the part.

Setup mode interactions mostly use 2-byte functions from the

host to cause the part to alter its behavior; these functions

also cause writes to the internal eeprom.

The concept of 'scope' is used to allow functions to operate

on individual keys or groupings of keys. The scope of

subsequent functions can be altered by short initial scope

instructions.

See Section 5 for protocol details.

4.2 SPI Port Specifications

The part has an SPI synchronous serial interface with the

following specifications at 12MHz oscillator frequency:

Max clock rate, Fck 3MHz

Data length 8 bits

Host command space, Tcm m 50µs

Response delay to host, Tdr1 Table 4-1, also, Sec. 6

Drdy delay from response, Tdr2 1µs to 1ms

Multi-byte return spacing, Tdr3 10µs to 2ms

The host can clock the SPI with the part in Slave mode at any

rate up to and including the maximum clock rate Fck. The

maximum clock rate of the part in Master mode is determined

by Setup ^Q (page 25).

The part can operate in either master-slave mode or

slave-only mode, and is thus compatible with virtually all

SPI-capable microcontrollers.

The SPI interface should not be used over long distances due

to problems with signal ringing and introduced noise etc.

unless suitably buffered or filtered with RC networks as

shown in Figures 4-6 and 4-7. Slower data rates with longer

RC timeconstants will provide enhanced resistance to noise

and ringing problems.

4.3 SPI Slave-Only Mode

Refer to Figures 4-1, 4-3 and 4-2. In Slave-only mode the

host must always be in Master mode, as it controls all SPI

activity including the clocking of the interface in both

directions. Unlike hardware SPI slaves, the QT60161B needs

processing time to respond to functions. DRDY’ is used to let

the host know when data is ready for collection; it indicates to

the host when data is ready in response to a command so

that the host can clock over the data.

This mode requires 5 signals to operate:

MOSI - Master out / Slave in data pin; used as an input for

data from the host at all times. This pin should be

connected to the MOSI pin of the host device.

MISO - Master in / Slave out data pin; used as an output for

data to the host at all times. This pin should be connected

to the MISO pin of the host device.

SCK - SPI clock - input only clock pin from host. The host

must shift out data on the falling edge of SCK; the

QT60161B clocks data in on the rising edge of SCK.

Important note: SCK must idle low just before and after

SS’ transitions either up or down, or the transmission will

fail; between bytes SCK should idle low.

SS’ - Slave select - input only; this pin acts as a framing

signal to the sensor from the host. This line must go low

just before and during reception of data from the host. It

must not go high again until the SCK line has returned low;

during data or echo response it must not go high until after

the host has sensed that DRDY’ has gone high from the

device. This pin must idle high. The SS’ pin has an internal

pullup resistor inside.

DRDY’ - Data Ready - active-low - indicates to the host that

the part is ready to send data back subsequent to a

command from the host. This pin idles high. The DRDY’

pin has an internal pullup resistor inside.

Internal pullup resistors note: The internal pullup resistors

can range from 35k to 120k ohms. If RC filtering is used on

the SPI lines per Figure 4-6, this resistance may not be low

enough to ensure adequate signal risetime and may need to

be augmented with external 10k pullups.

The host must wait until DRDY’ goes low before an SPI

transfer to retrieve data. For multi-byte responses, the host

must observe DRDY' to see when it goes high again after

each data byte, then low again, before executing another

transfer to get the next data byte. The host should send null

bytes (0x00) to retrieve data.

If the DRDY’ line does not go low after a command, the

command was not properly received or it was inappropriate.

The delay to DRDY’ low depends on the command and how

many bytes of data are being stored into eeprom; Table 4-1

shows the maximum delays encountered in most cases.

Absolute worst case delays are found in Section 6-5; these

timings occur only rarely, for example if the device happens

to be busy with adjacent key suppression calculations, which

occurs only at the moment when a key is first detected.

A typical Slave-only function sequence is as follows:

1) The host pulls SS’ low, then transfers a command to the

sensor. The host then releases SS’ to float high. DRDY’ is

unaffected in this step.

2) For 2-byte functions, (1) is repeated with a m50us delay.

3) When the sensor has the command echo or requested

data ready to send back to the host, it loads it into its SPI

4) The host detects that the sensor has pulled DRDY’ low

and in turn the host pulls SS’ low.

5) The host obtains the byte from the sensor by transmitting

a dummy byte (0x00) to the sensor.

6) The sensor releases DRDY’ to float high.

7) After the host detects that DRDY' has floated high the

host must allow SS’ to also float high.

8) For multi-byte responses, steps (3) through (7) are

repeated until the return data is completely sent.

Note that the host must release the SS’ line in step (7) even

between multiple byte responses because the QT60161B

waits for the SS’ line to return high before signalling that the

next byte is ready for collection.

Note also that the host should check the DRDY’ line and wait

for it to go high before transmitting another byte. Until the

DRDY’ line is released the sensor is still processing a data

return, even if the complete response data has been fully

transferred; the sensor may still be busy when the host

finishes the byte transfer and may not be able to digest a new

command immediately.

©Quantum Research Group Ltd.

www.qprox.com QT60161B / R1.03

See Section 3.15, page 10, for a description of the Alert pin

which can be used to reduce communication traffic.

4.4 SPI Master-Slave Mode

Refer to Figures 4-1, 4-2, and 4-4. In Master-Slave mode the

host and the sensor take turns being Master, with the host

always leading off in Master mode during an exchange. The

current Master always controls all 3 signal lines. The sensor

takes a variable amount of time to respond to the host,

depending on the nature of the function and its current and

pending tasks. The host, like the sensor, must idle in slave

mode when not sending a command.

Master/Slave requires 3 signals to operate:

MOSI - Master out / Slave in data pin - bidirectional - an input

pin while the host is transmitting data; an output when the

sensor is transmitting data. The MOSI of the host and

slave should be tied together. The MISO lines are not used

on either part and should be left open.

SCK - SPI clock - bidirectional - an input pin when receiving

data; an output pin when sending. The host must shift out

data on the falling edge of SCK; the QT60161B clocks data

in on the rising edge of SCK. Important note: SCK from

the host must be low before asserting SS’ low or high at

either end of a byte or the transmission will fail. SCK

should idle low; if in doubt, a 10K pulldown resistor should

be used. When the sensor returns data it becomes the

Master; data is shifted out by it on the falling edge of SCK

and should be clocked in by the host on the rising edge.

SS’ - Slave select - bidirectional framing control. When the

sensor is in slave mode, this pin accepts the SS’ control

signal from the host. In either data direction, SS' must go

low before and any during data transfer; it should not go

high again until SCK has returned low at the end of a byte.

In Master mode the sensor asserts control over this line, to

make the host a slave and to frame the data. This line

must idle high; the part includes an internal pullup resistor

and should be floated during idle times.

Internal pullup resistor note: The internal pullup resistor on

SS’ can range from 35k to 120k ohms. If RC filtering is used

on the SPI lines per Figure 4-7, this pullup resistance may not

be low enough to ensure adequate signal risetime and may

need to be augmented with external 10k pullups.

A command may consist of one or two bytes with a m50us

delay between command bytes. At the end of a full command,

the Master must go into Slave mode to await a response from

the sensor.

The sensor may take some time to process the host

command and respond. When it does so, it asserts SS’ low

and begins clocking its data. For multi-byte responses, the

bytes will be sent at intervals which may be somewhat

irregular depending on the request and the processing

load of the sensor. The host must be prepared to accept

the sensor data as it comes or there can be a data

overrun in the host. If the data returns too fast for the host

to accept it, the SPI clock rate should be lowered.

A typical Master-Slave function sequence is as follows:

1) Host enters Master mode. The sensor is already in

Slave mode.

2) The host pulls SS’ low, then transfers one byte of

command to the sensor via MOSI, then releases SS’ to

float high again.

3) For 2-byte functions, (2) is repeated with m50us spacings

between bytes.

4) The host immediately places its SPI port into Slave mode,

floating SCK and MOSI’; SS’ stays floating.

5) When the sensor has a command echo or data to send

back, it puts its SPI register in Master mode, taking control

over MOSI and SCK. SS' remains floating.

6) The sensor pulls SS’ low, then clocks out its response

byte to the host, then floats SS’ high again.

7) The sensor repeats (6) as necessary for multiple byte

responses.

8) The sensor returns to slave mode.

After the transmission sequence, the SPI lines float high or

are left to float in an indeterminate state (MOSI) until the next

transmission sequence is initiated by the host. The host

should wait for >1ms after a sequence before initiating

another transmission sequence.

See Section 3.15, page 10, for a description of the Alert pin

which can be used to reduce communication traffic.

©Quantum Research Group Ltd.

www.qprox.com QT60161B / R1.03

Figure 4-2 SPI Connections

Slave-Only Master-Slave

MOSI MOSI

MISOMISO

SCK SCK

DRDY

P_OUT

P_IN

Host M

T60

Vdd

MOSI MOSI

SCK SCK

DRDY

Host MCU QT60

MISOMISO

Figure 4-1 Communications Option Jumpers

Opt A Opt B

To M a t r i x

10K10K

L H H L

ParallelHighHigh

SPI, Master/SlaveLowHigh

UARTHighLow

SPI, Slave onlyLowLow

Interface TypeX0OPB (Pin 14)X0OPA (Pin 13)

4.5 UART Interface

Refer to Figures 4-1 and 4-5.

UART communications requires only 2 wires, TX and RX to

communicate with a host device. All communications must be

initiated by the host. The baud rate is determined by Setup

^Q (page 25); the maximum baud rate with a 12MHz oscillator

is 57.6K. UART communications uses the following settings:

©Quantum Research Group Ltd.

www.qprox.com QT60161B / R1.03

Table 4-1 Typical Tdr1 Response Delays (100µs sample ramp)

350µs350µs350µs

All other commands

350µs350µs350µs

Get keys pushed (K)

450µs450µs450µs

Get key errors (E)

500µs500µs500µs

Calibrate command (all keys)

65ms65ms65ms

Lock reference Level (L)

65ms65ms65ms

Setup - Put (affect 16 keys)

20ms20ms20ms

Setup - Put (affect 8 keys)

10ms10ms10ms

Setup - Put (affect 1 key)

2ms1ms500µsFunction Type

Burst Spacing

Figure 4-5 UART Timing

{from host}

Optional Byte 2

from host to sensor

Command Byte 1

from host to sensor

Tdr1

Response Byte or Echo

from sensor to host

Nth Byte from sensor

{N = command dependent}

76543210S

{from sensor}

76543210S

76543210S 76543210S

Tdr3

Figure 4-4 SPI Master/Slave Mode Timing

SCK

MOSI

Optional Byte 2

from host to sensor

Command Byte 1

from Host to sensor

Tdr1

Response Byte or Echo

from sensor to host

Nth Byte from sensor

{N = command dependent}

SS, SCK, MOSI originate from Host SS, SCK, MOSI originate from sensor

7 6543210 7 6543210 7 6543210 7 6543210

Floating

cm Tdr3

Figure 4-3 SPI Slave-Only Mode Timing

SCK

{from host}

MOSI

{from host}

MISO

{from sensor}

Invalid Data

Optional Byte 2Host Command Byte 1 Null Dummy Data Null Dummy Data

Invalid Data Response Data or Echo Nth Response Data

{N = command dependent}

DRDY

{from sensor}

{from host}

7 6543210

7 6543210 7 6543210

7 6543210

7 6543210 7 6543210

Tdr1

Tcm Tdr2

dr3

Baud rate 9,600 - 57,600

Data length 8 bits

Parity None

Stop bits 1

Host command space, Tcm m 50µs

Response delay to host, Tdr1 Table 4-1,

also, Sec. 6

Multi-byte return spacing, Tdr3 10µs to 2ms

The actual baud rate is determined by Setup ^Q (page 25).

A UART command may consist of one or two bytes with a

m50us delay between command bytes. At the end of a full

command, the host must await a response from the sensor.

The sensor may take some time to process the host

command and respond. When it does so, it sends back its

data. For multi-byte responses, the bytes will be sent at

intervals which may be somewhat irregular depending on the

request and the processing load of the sensor. The host must

be prepared to accept the sensor data as it comes or there

can be a data overrun in the host. If the data returns

too quickly for the host to accept it, the baud rate

should be lowered.

A typical UART communication sequence is as follows:

1) Host sends a byte to the sensor.

2) For 2-byte functions, a m50us delay is inserted by

the host and then the second byte is sent.

3) If the sensor has a command echo or data to send

back, it does so. The delay from step 2 to step 3 is

shown in Table 4-1. The delay between successive

response bytes (if they occur) is parameter Tdr3

noted above.

4) The sensor repeats (3) as necessary for multiple

byte responses.

5) The sensor waits for the next command.

The host should wait for >1ms after a sequence before

initiating another transmission sequence to be sure

that the sensor has completed any residual activities

from the prior command. Commands that are sent to

the host prematurely will be ignored.

4.6 Sensor Echo and Data Response

The devices respond to each and every valid

command from the host with at least one return byte.

In the case of functions that do not send data back to

the host, the part returns the command itself as an

echo, but only after the function has been processed to

completion; this also holds for 2-byte functions where

the second byte is an operand: in these cases the

return byte is an echo of the command, not the

operand.

One important exception to this is the recalibration

command ‘b’ which returns an acknowledgment

immediately rather than prior to the actual

recalibration.

Commands that return data do not send back a

command echo. If desired, the command byte can be

verified via the 'l' (lowercase L) function; see page 25.

The host should not transmit a new command until the

last command has been processed and responded to

completion, plus 1ms.

Commands that are not recognized are ignored, and the host

should monitor for timeouts to detect these conditions. If this

occurs a new command should not be sent until the specified

timeout condition has expired.

The maximum timings shown in Table 4-1 and Section 6-5

are guaranteed provided that the part is operating within its

burst timing limitations described in Section 5.7. If the burst

timing is in violation, the response time to a command may

take considerably longer.

4.7 Parallel Scan Port

The parallel port can be used to directly replace an electro-

mechanical or membrane keyboard. The port is electrically

equivalent to a 4x4 switch matrix with the exception that the

response to a host scan requires up to 100µs. The XS inputs

(pins 19..22) are active high; only one XS line should ever be

driven high at a time (except for error scan, noted below); the

©Quantum Research Group Ltd.

www.qprox.com QT60161B / R1.03

Figure 4-6 Filtering; SPI Slave-Only Connections

MOSI

MISO

SCK

DRDY

QT60161 Circuit

220

47pF Ra

RESET

Host MCU

100

22pF

Xn X drives

(1 of 4

shown)

Y Lines

(1 of 4

shown)

10K

1nF

10K

SCK

MISO

MOSI

(MS not

shown)

P_IN

P_OUT1

P_OUT2

Figure 4-7 Filtering; SPI Master-Slave Connections

MOSI

MISO

SCK

DRDY

QT60161 Circuit

220

47pF Ra

RESET

Host MCU

100

22pF

Xn X drives

(1 of 4

shown)

Y Lines

(1 of 4

shown)

1nF

10K

MOSI

SCK

MISO

(MS not

shown)

P_OUT

470pF2,20093.75kHz

270pF1,000187.5kHz

120pF1,000750kHz

47pF6803MHz

CaRaSPI Clock Rate

Recommended Values of Ra & Ca for Figures 4-6 and 4-7

output response is found on the YS lines (pins 23..26), and

these are also active high. The bit pattern found on the YS

lines indicates any keys that are touched; like a real matrix,

the device can set multiple bits on the YS lines.

The host should scan to individual lines XS0..XS3. XS0 maps

to matrix drive line X0 (pin 13). The response on YS0 maps to

matrix line Y0. Thus, the scan port logic exactly mimics the

wiring and scanning of the matrix keys.

The parallel scan port operates on a continuous basis, but is

slower to react when either serial port is in operation. If either

serial port is operational, the scan port updates with every

acquisition burst, i.e. 16 times during a complete scan of the

matrix.

For a full-time higher speed scan port response, it should be

enabled as the sole interface via the option jumper settings

shown in Figure 4-1. The port itself is found on pins 19

through 26 (Figure 3-2). In this dedicated mode, the scan port

outputs within 100µs of receiving a scan input from the host.

Error scan: The host can extract error information from the

scan port by setting all XS lines to logical '1' simultaneously.

The part then returns a high level on any YS lines

corresponding to Y matrix lines having key errors. Thus a

single YS bit, if high, could indicate errors on any or all of 4

keys. Errors are reported for the following conditions:

a. Key(s) are currently recalibrating

b. Key(s) tried to calibrate 5 times and failed each time

c. Key(s) signal references are under- or over- limit

It is not possible to determine the cause of the error or

specific key(s) in error via the parallel scan port.

4.8 Eeprom Corruption

The device stores its Setup data in an internal eeprom which

can be readily altered via Put mode commands. Sometimes

noise on Vdd, the SPI lines or Reset pin can cause eeprom

corruption which can be difficult or inconvenient to correct.

The device should always be left in Get mode to prevent

spurious commands from corrupting the eeprom. The Get

command should ideally be repeated every second or so to

ensure that if noise on the SPI lines causes a false Put mode

command that it does not last long. Preferably, the ‘l’

command (lowercase ‘L’) should be used to verify that the Put

command has succeeded.

Flash backup: The part backs up the entire eeprom array

into onboard Flash rom after one or more Setup write

commands have been issued and the part is then reset.

During normal operation the part constantly compares the

Flash area with the eeprom array to ensure the two sections

match. If an eeprom error is detected, the device sets an

error flag (bit 4) in the general device status byte (Command

‘7’, page 19) which can be read by the host device. The LED

output also becomes active. If the bit 4 error flag is set, the

host should immediately induce a device reset.

Bit 4 is also set if an intentional write has been made to

eeprom, but not yet copied into Flash via the reset process. It

is perfectly acceptable to continue altering any number of

Setup parameters prior to doing the reset, ignoring this bit.

During power up or after a reset, the device compares the

Flash area with eeprom, and if there is a discrepancy the

eeprom is refreshed from Flash, unless an intentional write

was detected in which case the Flash is updated from the

eeprom. As intentional writes in Put mode should only occur

during manufacture, it is normally safe to assume that

eeprom changes during normal run mode are errors.

The host can also periodically test the checksum of the

eeprom as a backup mechanism to the bit 4 error flag.

The uppercase ‘L’ command, Lock Reference Levels, also

writes data to eeprom, and this data also has the potential to

become corrupted. This data is also backed up in Flash so

that it can be recovered, and an error in this data will also set

bit 4 and also alter the checksum. Also, the ‘L’ command only

operates if the device is in Put mode as a further protection.

Flash memory has a limit of 1,000 write cycles, so

copy-to-Flash should not be used often.

©Quantum Research Group Ltd.

www.qprox.com QT60161B / R1.03

5 Commands & Functions

The command structure is designed to minimize control and

data traffic. All repetitive data and status commands from the

host are single-byte, and most commands result in single-

byte device responses. Behavioral setup commands involve

multiple bytes but these are infrequently used.

Special 'scope' commands exist to restrict subsequent

commands to a specific key or range of keys. This control

structure permits most matrix keys, which are usually

identical in shape and size, to be programmed 'in bulk' using

a 'global' scope command, followed by a scope restriction to

specific key(s), followed by more key programming, to

prevent the need for tedious key-by-key programming across

an entire matrix.

There are four types of commands:

Direction - Determine whether subsequent commands are

used to get data from or put data to the part;

Scope - Restrict the range of effect of subsequent

commands to a specific set of keys;

Status - Cause the part to respond with key information,

such as detections, signals, error codes, and the like;

Setup - Modify functionality such as burst length, threshold

levels, drift compensation characteristics, etc.

Supervisory - Special functions such as diagnostics,

calibration, etc. which affect the part as a whole.

All command types can be intermixed. Even during normal

device operation it is possible to use Setup and Supervisory

functions to alter key behavior on the fly. There is no special

'setup mode'.

Get/Put, Scope, and many Supervisory functions are volatile

and do not persist after a power down or reset cycle. Some

Supervisory commands require that the part be reset in order

for the new settings to take effect.

Note that the Setup functions write to eeprom and require

extra time for a response back to the host. Also note that as

with all eeprom memories there is a recommended lifetime

limit to the number of writes; this limit is 100,000 cycles.

Command functions are summarized in Section 5-6.

It is highly advised to test the device checksum

(command ‘6’, page 18) or individual settings or the

general device status (‘7’) once Setups have been

programmed into the part, each time the part is powered

up and periodically while running.

The part backs up all eeprom locations into Flash, from

which data is restored automatically following a reset if

eeprom corruption is detected. The part should also be

reset after any Put command(s) in order to force the copy

of eeprom data into Flash. See Section 4.8.

5.1 Put / Get Direction Commands

Setup commands can be used to either send control

information to the part for programming into its internal

eeprom, or to extract the current setting of this information.

The same Setup function can do either. To accomplish this

the device relies on direction control via the Get and Put

commands. In Get mode, a Setup command will return

information. In Put mode, the behavior of the device is

altered, and often a second operand byte must be sent.

The powerup or reset default mode is Get. The current

Get/Put mode persists until countermanded by a different

Get/Put command or until the device is reset or powered off.

It is advisable to use Put mode only when actually writing

Setups to the device, which will happen infrequently; the part

should normally be left in Get mode. Get mode acts as a lock

to prevent accidental changes to the internal eeprom.

Multiple direction commands of the same type (g, g, g, g ...)

are harmless and can be used to insure that the part does not

accidentally enter Put mode for a prolonged period, for

example due to noise glitches on the SPI lines. The 'g'

command can be repeated every few seconds.

g 0

67 - G

OMMAND

n/an/an/an/aGet

0x67n/a1n/aPut

Return

2nd B

te Ran

tes / Cm

Scop

Lowercase 'G'. The 'g' command causes the device to treat all

subsequent Setup commands as 'Gets'; after, when a Setup

command is received from the host the part will respond by

sending back the current status of that Setup parameter.

The 'g' command is always single-byte and echoes back

itself.

p 0

70 - P

OMMAND

n/an/an/an/aGet

0x70n/a1n/aPut

Returns2nd Byte RangeBytes / CmdScope

Lower case 'p'. The 'p' command causes the device to treat

all subsequent Setup commands as 'Puts'; after, when a

2-byte Setup command is received from the host the part will

respond by programming in the desired parameter for the

key(s) which are affected.

The 'p' command is always single-byte and echoes back

itself.

©Quantum Research Group Ltd.

www.qprox.com QT60161B / R1.03

5.2 Scope Commands

The host should always set the scope parameter when

initializing the part during normal operation as well as during

setup. Scope commands are persistent and apply to all

subsequent functions that are affected by scope, until a

different scope command is issued. On powerup or after reset

the device defaults to scope = 'all keys'.

Many functions only address one key regardless of the

current scope; in these cases the key being addressed is

always the key last set by the ‘s’ or ‘x’ and ‘y’ commands. If

the ‘s’ command was last set to key 9, then even though the

‘S’ command was issued afterwards the one-key scope will

remain key ‘9’. Similarly if ‘x’ was set to 2 and ‘y’ to 3, then

the one-key scope will remain key x=2 / y=3 (key #14). This

rule operates for either Put or Get commands.

Key numbering convention: The numbering of keys goes by

row then column. For example, the key in row X=3, column

Y=1 (X3Y1) is key 7. The formula for conversion of an X-Y

location to a key number is:

key number = X_row + (Y_column x 4)

Row and column numbers are per Fig. 1-5. Keys are acquired

in this same burst sequence, i.e. X0Y0, X1Y0, X2Y0 etc.

s 0

73 - S

PECIFIC

COPE

n/an/an/an/aGet

0x730x00..0x0F2n/aPut

Return

2nd B

te Ran

tes / Cm

Scop

Lowercase 'S'. Targets a specific individual key for all further

functions that are affected by scope. The second byte must

contain a binary key number from 0..15.

S 0

53 - A

EYS

COPE

n/an/an/an/aGet

0x53n/a1n/aPut

Return

2nd B

te Ran

tes / Cm

Scop

Uppercase 'S'. Addresses all keys in the matrix for all further

functions that can target a group of keys.

x 0

78 - R

EYS

COPE

n/an/an/an/aGet

0x780x00..0x032n/aPut

Returns2nd Byte RangeBytes / CmdScope

Lowercase 'X'. Targets keys in a specific row for functions

that can address key groups. The second byte must contain a

row number from 0..3.

y 0

79 - C

OLUMN

EYS

COPE

n/an/an/an/aGet

0x790x00..0x032n/aPut

Return

2nd B

te Ran

tes / Cm

Scop

Lowercase 'Y'. Targets keys in a specific column for functions

that can address key groups. The second byte is a binary

column number from 0..3.

5.3 Status Commands

Status commands cause the sensor to report back

information related to keys and their signals.

It is not necessary to set the part to Get mode with these

commands, although it is advised to leave the part in Get

mode as a normal precaution (see Section 5.1)

0 0

30 - S

IGNAL

FOR

INGLE

0..0xFFFF211Get

n/an/an/a n/aPut

Return

# B

tes Rtn

tes / Cm

Scop

Numeric '0'. Returns the signal level in 16-bit unsigned binary

for one key whose location is determined by scope. The least

significant byte is returned first.

Note that the signal direction is inverted: decreasing values

correspond to more touch due to the physics of key detection

described in Section 1.1.

1 0

31 - D

ELTA

IGNAL

FOR

INGLE

0x00..0xFF111Get

n/an/an/a n/aPut

Returns# Bytes RtndBytes / CmdScope

Numeric '1'. Returns the value {Reference - Signal} in

unsigned 8-bit binary for one key whose location is

determined by scope. If Signal > Reference, the result is

truncated to zero. The return value is also limited to 255

(0xFF).

Increasing amounts of this value correspond to increasing

amounts of touch as the sign of signal is inverted (see 0x30

above).

2 0

32 - R

EFERENCE

ALUE

0..0xFFFF211Get

n/an/an/a n/aPut

Returns# Bytes RtndBytes / CmdScope

Numeric '2'. Returns the Reference value in unsigned 16-bit

binary for one key whose location is determined by scope.

The least significant byte is returned first.

5 0

35 - D

ETECTION

NTEGRATOR

OUNTS

0x00..0xFF111Get

n/an/an/a n/aPut

Return

# B

tes Rtn

tes / Cm

Scop

Numeric '5'. Returns the Detection Integrator counter value

for one key whose location is determined by scope. This

function is useful primarily for circuit diagnostics.

6 0

36 - E

EPROM

HECKSUM

00..0xFF11n/aGet

n/an/an/an/aPut

Return

# B

tes Rtn

tes / Cm

Scop

Numeric '6'. Returns the entire eeprom checksum. This

function is useful primarily for diagnostics and should

periodically be used to check for valid eeprom contents.

The checksum should be computed when the entire device's

settings, including the locked reference levels ('L' command)

are known. The host can then periodically test the checksum

to validate eeprom integrity. If needed, the eeprom can then

©Quantum Research Group Ltd.

www.qprox.com QT60161B / R1.03

be reprogrammed by the host or the device can be reset to

allow the eeprom to be updated from Flash memory (see

Section 4.8).

The checksum is a simple 8-bit carry fold-back type. Changes

to multiple Setups can generate identical checksums.

Changes to one location only will always produce a different

checksum. An identical change to 2, 4, 8, or all 16 keys is

more prone to generating an identical checksum. A unique

checksum can be obtained again by altering any Setup for

another key (i.e. an unused key) to be different.

After any Setups change, the checksum will not be valid until

after the device has been reset.

Note that the status byte returned by the ‘7’ command

contains a bit that is set if there is an error in eeprom data;

this feature operates independently of the checksum

command.

There is no put version of the command.

7 0

37 - G

ENERAL

EVICE

TATUS

0x00..0x1F11n/aGet

n/an/an/a n/aPut

Return

# B

tes Rtn

tes / Cm

Scop

Section 2.11, p. 7

Numeric '7'. Returns the part's general status byte which is a

4-bit pattern as follows:

Bit 0: 1= one or more keys are in detection

Bit 1: 1= one or more keys are recalibrating

Bit 2: 1= one or more keys are reporting errors

Bit 3: 1= sync fail; the part is not synchronized to an

external source (if in that mode; see Section 3.14).

Bit 4: 1 = Eeprom / Flash contents discrepancy

Higher bits report as 0's and are not used.

This command can be used as a general 1-byte status

response; if one or more bits are set, the host can take

further relevant action to narrow down the specific issue, such

as which key is being touched or in error, via other

commands.

> 0

20 - S

IGNAL

EVELS

FOR

ROUP

0..0xFFFF8 or 3214, 16Get

n/an/an/a n/aPut

Return

# B

tes Rtn

tes / Cm

Scop

Space character. Same function as 0x30 above except

returns a group response for 4 keys (if Scope = row or

column) or 16 keys (if Scope = 'all keys'). If no group scope

has been selected, returns data for all keys (32 bytes).

Two bytes are returned for each key; the least significant byte

is always returned first.

! 0

21 - D

ELTA

IGNALS

FOR

ROUP

0x00..0xFF4 or 1614, 16Get

n/an/an/a n/aPut

Return

# B

tes Rtn

tes / Cm

Scop

Exclamation character. Same function as 0x31 above except

returns a group response for 4 or 16 keys depending on

scope. If no group scope has been selected, returns data for

all 16 keys (16 bytes). The values returned are limited to the

range 0..255.

" 0

22 - R

EFERENCE

EVELS

FOR

ROUP

0..0xFFFF8 or 3214, 16Get

n/an/an/a n/aPut

Return

# B

tes Rtn

tes / Cm

Scop

Double quote character. Same function as 0x32 above except

returns a group response for 4 or 16 keys depending on

scope. If no group scope has been selected, returns data for

all 16 keys (32 bytes).

% 0

25 - D

ETECT

NTEGRATOR

OUNTS

FOR

ROUP

00..0xFF4 or 1614, 16Get

n/an/an/an/aPut

Return

# B

tes Rtn

tes / Cm

Scop

Percent character. Same function as 0x35 above except

returns a group response of 4 bytes (Scope = row or column)

or 16 bytes (Scope = 'All keys'). If no group scope has been

selected, returns data for all 16 keys.

e 0

65 - E

RROR

ODE

FOR

ELECTED

00..0x0F111Get

n/an/an/a n/aPut

Returns# Bytes RtndBytes / CmdScope

Section 2.11, p. 7

Lowercase 'E'. Returns the error byte for a selected key

defined by the 's' command. A 4-bit pattern is returned:

FRHLuuuu

b0b1b2b3b4b5b6b7

F:1= failed last full recalibration attempt

R:1= key is in process of full recalibration

H:1= key reference is high (above normal bounds)

L:1= key reference is low (below normal bounds)

u:undefined

Refer also to Section 2.10.

F, Bit 0 is set if it failed to calibrate properly during a forced

recalibration. The sensor will automatically make 5 sequential

attempts at recalibration before setting this flag.

R, Bit 1 is set if the key is in the process of a full

recalibration. When bit 1 is set, bits 2 and 3 are cleared.

H, Bit 2 when set indicates that the key's reference level has

exceeded the upper boundary described in Section 2.8 and

as defined by Command ^N (page 23).

L, Bit 3 when set indicates that the key's reference level falls

below the lower boundary described in Section 2.8 and as

defined by Command ^O (page 23).

If either H or L are set, it means that the key is probably

defective.

©Quantum Research Group Ltd.

www.qprox.com QT60161B / R1.03

E 0

45 - E

RROR

ODES

FOR

ROUP

0x00..0xFF1 or 411, 4, 16Get

n/an/an/a n/aPut

Return

# B

tes Rtn

tes / Cm

Scop

Section 2.11, p. 7

Uppercase 'E'. Returns general error codes for a range of

keys defined by scope. Returns either 1 or 4 bytes depending

on whether a single key, row, column, or entire matrix are

selected.

The bitfields for single key scope are the same as for 'e'

above.

The bitfields for a single row (X) are:

0Y1Y2

3----

b0b1b2b3b

b6b7

The bitfields for a single column (Y) are:

X0X1X2X3----

b0b1b2b3b4b5b6b7

The bitfields for a global response are:

X0Y3

X1Y3

X2Y3

X3Y3

----byte4

X0Y2

X1Y2

X2Y2

X3Y2

----byte3

X0Y1

X1Y1

X2Y1

X3Y1

----b

te2

X0Y0

X1Y0

X2Y0

X3Y0

----b

te1

b0b1b2b3b

b6b7

Byte 1 is the first returned byte in the sequence.

In all the above examples a '1' in a bit position indicates that

there is some type of error associated with the key. The use

of the 'e' command (or 'E' with scope set to a specific key) will

specify the nature of the error.

k 0

6B - R

EPORTING

IRST

OUCHED

00..0xFF11n/aGet

n/an/an/a n/aPut

Return

Rtn

tes / Cm

Scop

Section 2.11, p. 7

Lowercase 'K'. Returns a byte that indicates which (if any) key

has been touched. The byte is structured as follows:

k0k1k2k3---m

b0b1b2b3b4b5b6b7

Bits are used as follows:

m - if '1', indicates that yet another key is active

k0..k3 - indicates the key number of a first detected key,

in the range 0..15 (0x00..0x0F).

If a reported key drops out while other keys are active, 'k' will

report one of the other active keys, but there is no rule for

which of the next keys gets reported in k0..k5.

If the byte returned has a value of 255 (0xFF), then no key

has been detected.

0x4B - Key Touch Reporting for Group

0x00..0xFF1 or 411, 4, 16Get

n/an/an/a n/aPut

Return

# B

tes Rtn

tes / Cm

Scop

Section 2.11, p. 7

Uppercase 'K'. Returns 1 or 4 bytes depending on the current

scope. The byte(s) returned contain a bit pattern which

indicates touched keys. A scope of a single key, a row or a

column will return one byte. A scope of all keys will return 4

bytes.

The bitfields for a single key are:

key-------

b0b1b2b3b4b5b6b7

The bitfields for a single row (scope is X) are:

1Y2Y3----

b0b1b2b3b

b6b7

The bitfields for a single column (scope is Y) are:

X0X1X2X3----

b0b1b2b3b4b5b6b7

The bitfields for a global report are:

X0Y3

X1Y3

X2Y3

X3Y3

----byte4

X0Y2

X1Y2

X2Y2

X3Y2

----byte3

X0Y1

X1Y1

X2Y1

X3Y1

----b

te2

X0Y0

X1Y0

X2Y0

X3Y0

----b

te1

b0b1b2b3b

b6b7

Byte 1 is the first returned byte in the sequence.

In all the above examples a '1' in a bit position indicates that

the key is touched; a '0' indicates no touch.

©Quantum Research Group Ltd.

www.qprox.com QT60161B / R1.03

5.4 Setup Commands

Setup functions are those that alter the behavior a key or a

group of keys. The setups are programmed into eeprom

locations in the part and ordinarily do not need to be

reprogrammed once set. However it is possible to change a

setup while the device is in normal operation without

interrupting the sensing function of the part.24

Setup functions alter the internal eeprom, and this requires a

much longer time to complete than other commands; see

Table 4-1.

Setup 'put' commands become effective immediately after the

echo response of the command byte unless otherwise noted;

some setups require that the key(s) being altered be

recalibrated with the 'b' command (page 24) before they take

effect.

^A 0

01 - N

EGATIVE

ETECT

HRESHOLD

0x04..0x40n/a11Get

0x010x04..0x4021, 4, 16Put

ReturnsByte 2 RangeBytes / CmdScope

Section 2.1, p. 5

Ctrl-A. In Put mode, the command followed by a setting is

programmed into eeprom for the key(s) affected by scope.

1, 4, or 16 keys may be affected. Valid decimal values are:

45678101215

17 20 25 30 35 45 55 64

Values other than the above will be rounded down.

In Get mode, the command will return a single byte according

to the current scope rules (Section 5.2).

This controls key sensitivity by setting the counts of signal

delta needed to cause a detect. Higher = less sensitive.

Numbers should be 6 or greater under most conditions to

reduce the probability of noise detection. Numbers greater

than 20 indicate that the burst length is probably too high.

This setup interacts with Burst Length (^F).

^B 0

02 - P

OSITIVE

ETECT

HRESHOLD

0x04..0x40n/a11Get

0x020x04..0x4021, 4, 16Put

ReturnsByte 2 RangeBytes / CmdScope

Section 2.2, p. 5

Ctrl-B. In Put mode, the command followed by a setting is

programmed into eeprom for the key(s) affected by scope. 1,

4, or 16 keys may be affected. Valid decimal values are:

45678101215

17 20 25 30 35 45 55 64

Values other than the above will be rounded down.

In Get mode, the command will return a single byte according

to the current scope rules (Section 5.2).

This setup controls the ability of a key to recalibrate quickly

should the signal transition positive quickly, as when a touch

is prolonged enough to cause a recalibration, and when the

key is then 'untouched'. This condition can also be caused by

a foreign object being removed from a key. The value should

normally be set between 6 and 10 counts. If the value is very

high, the key will still recover by means of the drift

compensation process, albeit more slowly.

^C 0

03 - N

EGATIVE

HRESHOLD

YSTERESIS

0x01..0x03n/a116Get

0x030x01..0x03216Put

ReturnsByte 2 RangeBytes / CmdScope

Section 2.3, p. 5

Ctrl-C. In Put mode, the command followed by a setting is

programmed into eeprom for all keys only. The value should

be from 0 to 3, representing hysteresis as follows:

0:50%

1:25%

2:12.5%

3:0% (no hysteresis)

Values other than the above will be rounded down.

The percentage is the distance from the threshold level to the

reference level. The hysteresis level is always closer to the

threshold point than to the reference point. 25% is a

reasonable value under most conditions.

As this parameter is common to all keys, Put and Get

operations send or return only one byte.

^D 0

04 - P

OSITIVE

HRESHOLD

YSTERESIS

0x01..0x03n/a116Get

0x040x01..0x03216Put

Return

te 2 Ran

tes / Cm

Scop

Section 2.3, p. 5

Ctrl-D. Identical in operation to ^C above except this applies

to positive 'detections' used to recalibrate the sensor (see ^B

above for details). Uses same hysteresis values as ^C above.

^F 0

06 - B

URST

ENGTH

0x00..0x40n/a11Get

0x060x00..0x4021, 4, 16Put

ReturnsByte 2 RangeBytes / CmdScope

Section 3.5, p. 8

Ctrl-F. In Put mode the command sets the burst length of one

or more keys, according to the current scope. Valid decimal

values are:

012345710

12 15 20 25 30 40 50 64

Values other than the above will be rounded down.

In Get mode, the command will return a single byte according

to the current scope rules (Section 5.2).

^F sets the length of the acquisition burst on a key by key

basis. This setting is directly proportional to signal gain. This

setup interacts with Negative and Positive Threshold (^A and

^B). Increasing ^F can allow for higher threshold levels and

more robust signals, at the expense of increased radiated

emissions and reduced Cx load capacity.

Special condition: If the value for ^F for a key is set to zero

the burst disabled and the key will not function; the key will

report back with an error code. The timing for the 'phantom

burst' will be preserved so that overall key scan timing will

remain unchanged.

©Quantum Research Group Ltd.

www.qprox.com QT60161B / R1.03

^G 0

07 - B

URST

PACING

0x00..0x02n/a116Get

0x070x00..0x02216Put

Return

te 2 Ran

tes / Cm

Scop

Section 3.8, p. 9

Ctrl-G. In Put mode, sets the spacing between successive

acquire bursts for the entire matrix.

The second byte indicates the spacing to be set according to

the following table:

0:500µs (0.5ms)

1:1000µs (1ms)

2:2000µs (2ms)

Values higher than 2 will be truncated to 2.

Longer delay times equate to slower matrix scanning. At

lower delay times (faster rep rates) there can be conflicts with

long burst lengths and long conversion times which will

prevent proper operation; see also Section 3.6, and Section

5.7.

Burst spacing also affects recalibration time; see Section

2.10.

The scope for this function is always 'all keys'.

^H 0

08 - N

EGATIVE

RIFT

OMPENSATION

ATE

0x01..0x64n/a11Get

0x080x01..0x6421, 4, 16Put

ReturnsByte 2 RangeBytes / CmdScope

Section 2.4, p. 5

Ctrl-H. In Put mode, sets the rate of drift compensation used

during periods of non-detection, in the negative signal

direction. Valid decimal values are:

1234681012

15 20 25 33 45 60 75 100

Values other than the above will be rounded down.

These numbers correspond to the amount of drift

compensation applied, in 100ms/count of reference change,

for signals which are negative with respect to the reference

level, i.e. in the same direction as legitimate detections.

Higher numbers equate to slower drift compensation.

Overcompensation (too fast) can result in the suppression of

legitimate detections. Under-compensation can result in

inadequate compensation for rapid environmental changes.

Values of 15 to 45 (1.5 to 4.5 secs/count) are considered

normal under most conditions.

Drift compensation does not occur while the signal has

passed below the negative threshold level or subsequently

remained below the negative hysteresis level.

In Get mode, the command will return a single byte according

to the current scope rules (Section 5.2).

The scope in Put mode can be one key, a row or column, or

all keys.

^I 0

09 - P

OSITIVE

RIFT

OMPENSATION

ATE

0x01..0x64n/a11Get

0x090x01..0x6421, 4, 16Put

Return

te 2 Ran

tes / Cm

Scop

Section 2.4, p. 5

Ctrl-I. Same as ^H above in all respects, except operates

only when the signal is positive with respect to the reference

level, i.e. in an abnormal direction. It is usually desirable to

set this rate much faster than for ^H, i.e. to a lower number.

Valid decimal values are:

1234681012

15 20 25 33 45 60 75 100

Values other than the above will be rounded down.

Values of 4 to 10 (0.4 to 1.0 secs/count) are considered

suitable for most systems.

Positive drift compensation continues to operate even if the

signal has exceeded the positive threshold.

^J 0x0A - N

EGATIVE

ETECT

NTEGRATOR

IMIT

0x00..0xFFn/a11Get

0x0

0x00..0xFF21, 4, 16Put

Return

te 2 Ran

tes / Cm

Scop

Section 2.6, p. 6

Ctrl-J. In Put mode, sets the detection integration limit for

one or more keys according to scope.

The unit of measure is a burst, i.e. a setting of 5 means that a

detection must be sensed 5 bursts in sequence. A burst for a

key occurs once every complete matrix scan. The second

byte must be one of the following values (shown in decimal):

0123571015

20 32 45 60 90 123 175 255

Values other than the above will be rounded down.

In Get mode, the command will return a single byte according

to the current scope rules (Section 5.2).

This setup can be used as a noise filter, or as a mechanism

to intentionally slow down key reaction time in order to require

a long user touch.

Special condition: If the value for ^J is set to zero the key is

disabled, but the burst for the key is still generated.

©Quantum Research Group Ltd.

www.qprox.com QT60161B / R1.03

^K 0x0B - P

OSITIVE

ECALIBRATION

ELAY

0x00..0xFFn/a11Get

0x0B0x00..0xFF21, 4, 16Put

Return

te 2 Ran

tes / Cm

Scop

Section 2.7, p. 6

Ctrl-K. In Put mode, sets the delay until recalibration, timed

from when the signal first crosses the positive threshold.

The second byte controls the delay in 100ms increments, and

must be one of the following valid values:

0123571015

20 32 45 60 90 123 175 255

Values other than the above will be rounded down. As an

example, a value of 60 will cause a 6-second delay.

In Get mode, the command will return a single byte according

to the current scope rules (Section 5.2).

Special condition: If ^K is set to zero this feature is disabled

and the key will never auto-recalibrate on positive transitions;

however drift compensation will still operate.

^L 0x0C - N

EGATIVE

ECALIBRATION

ELAY

0x00..0xFFn/a11Get

0x0C0x00..0xFF21, 4, 16Put

Return

te 2 Ran

tes / Cm

Scop

Section 2.5, p. 6

Ctrl-L. In Put mode, sets the delay until recalibration, timed

from when the signal first crosses below the negative

threshold as defined by ^A.2.5

The second byte represents the delay in 100ms increments,

and must be one of the following valid values:

0123571015

20 32 45 60 90 123 175 255

Values other than the above will be rounded down. As an

example, a setting of 85 will cause delays of 6 seconds.

In Get mode the function returns a single value only; if scope

is set to row, column, or all, only the value for the lowest

ranking key in the group will be returned.

Special condition: If the value for ^L is set to zero this

feature is disabled and the key will never auto-recalibrate

after a prolonged touch.

^M 0x0D - I

NTRA

-B

URST

ULSE

PACING

0x01..0x0An/a116Get

0x0D0x01..0x0A216Put

Return

te 2 Ran

tes / Cm

Scop

Section 3.7, p. 9

Ctrl-M. In Put mode, sets the amount of time between

individual pulses in a burst.

The second byte must be in the range of 1 to 10 decimal;

other values will be ignored. The setting applies to all keys.

The value corresponds to the timing between pulses within a

burst, in microseconds. For example, a setting of 5 will set the

pulse spacing to 5 microseconds.

In Get mode the function returns the current value of ^M.

Intra-burst pulse spacing controls the fundamental frequency

of the burst and can have a strong effect on radiated

emissions from the matrix control panel. It can also have an

effect on susceptibility to external EMI if the external fields are

close in periodicity to the burst spacing.

^N 0x0E - P

OSITIVE

EFERENCE

RROR

AND

0x00..0xFFn/a116Get

0x0E0x00..0xFF216Put

Return

te 2 Ran

tes / Cm

Scop

Section 2.8, p. 6

Ctrl-N. In Put mode, sets the amount of tolerable positive

deviation in the reference level for all keys, in tenths of a

percent, with regard to the 'locked' reference value for each

key. The setup is global in nature and affects all keys equally.

Valid values are from 0 to 255 decimal. The percentage

applied is one tenth the operand's decimal value.

In Get mode the function returns the current setting of ^N.

This setup is used to define the limit of possible positive

reference deviation with respect to a factory setting, which is

used in turn to set an error flag for key(s) whose reference

level rises above the designated error band. If for example

this setting is set to 50, and the device is calibrated and

reference levels are locked (see command 'L', Lock

Reference Levels, page 24) into the part by the OEM, then in

the future if the reference level of a key should rise 5% over

its Locked reference level then the key will report back an

error flag via commands 'e' or 'E'.

Guardbands can be used to detect circuit faults as well as

extremes of temperature or moisture on the circuitry.

Special condition: If the value is set to zero, this feature is

disabled.

^O 0x0F - N

EGATIVE

EFERENCE

RROR

AND

0x00..0xFFn/a116Get

0x0F0x00..0xFF216Put

Return

te 2 Ran

tes / Cm

Scop

Section 2.8, p. 6

Ctrl-O. In Put mode, sets the amount of tolerable negative

deviation in the reference level for all keys, in tenths of a

percent, with regard to the 'locked' reference value for each

key. The setup is global in nature and affects all keys equally.

Valid values are from 0 to 255 decimal. The percentage

applied is equal to the decimal value divided by 10, thus, a

value of 20 equates to a 2% decrease (i.e. the lower

boundary becomes 98% of the locked reference level).

In Get mode the function returns the current setting of ^M.

This setup is identical in nature to ^N except that it governs

negative reference deviations.

Special condition: If the value is set to 0, this feature is

disabled.

www.qprox.com QT60161B / R1.03

^P 0x10 - A

DJACENT

UPPRESSION

(‘AKS’)

0x00, 0x01n/a11Get

0x100x00, 0x0121, 4, 16Put

Return

te 2 Ran

tes / Cm

Scop

Section 2.9, p. 6

Ctrl-P. In Put mode, instructs logic for the keys specified by

the current scope to suppress a pending touch detection

under certain signal conditions.

Valid 2nd byte values for this function are:

0:AKS off {default}

1:AKS on

In Get mode, the command will return a single byte according

to the current scope rules (Section 5.2).

AKS functions to suppress detections from water films which

can 'spread' a touch signal from the touched key to adjacent

keys.

AKS is also useful for panels with tightly spaced keys, where

a fingertip can partially overlap an adjacent key. This feature

will act to suppress the signals from the unintended key(s).

AKS only operates across keys that have been AKS-enabled;

signal strength comparisons are not made with non-

AKS-enabled keys.

Unused keys with burst lengths of zero are also ignored for

purposes of AKS.

5.5 Supervisory / System Functions

Supervisory functions report or control miscellaneous

functions that affect overall chip control, testing, or

diagnostics. All supervisory functions ignore scope except

where noted.

6 0

36 - E

EPROM

HECKSUM

00..0xFF11n/aGet

n/an/an/an/aPut

Returns# Bytes RtndBytes / CmdScope

See page 18.

L 0x4C - L

OCK

EFERENCE

EVELS

n/an/an/an/aGet

0x4C0x00216Put

Returns2nd ByteBytes / CmdScope

Section 2.8, p. 6

Uppercase 'L'. This is a put-only command that locks the

reference levels of the device into eeprom for all keys, for

boundary checking purposes over the product's life.

The whole command – 'L' followed by a null (0x00) - must be

received within 100ms without any intervening byte, or the

command will fail. The part must be in Put mode for this

command to work.

The scope of this command is always 'all keys'.

This function records to eeprom the signal reference for all

keys. The locked reference levels are used to compute

boundary checks immediately after the command has

finished. The results of this command to not take effect until

the part has been reset.

Due to the large number of bytes written to eeprom by this

command, there is a significant delay from the second byte

until the return echo is sent back to the host.

This command should be used only during production. There

is no get version of the command.

b 0x62 - R

ECALIBRATE

EYS

n/an/an/an/aGet

0x62n/a11, 4, 16Put

Return

2nd B

tes / Cm

Scop

Section 2.10, p. 7; Section 3.13.

Lowercase 'B'. This is a put-only command that causes the

keys selected by scope to recalibrate. The part must be in Put

mode for this command to work.

The return byte is sent before the keys have calibrated. While

keys are in recalibration, status of the keys can be

determined using the 'e' or 'E' commands.

If 'b' is sent while key(s) are already in the middle of

recalibration, the affected key(s) will abandon the old

calibration cycle and start a new one.

There is no get version of the command.

www.qprox.com QT60161B / R1.03

l 0x6C - R

ETURN

AST

OMMAND

HARACTER

0x00..0xFF11n/aGet

n/an/an/an/aPut

Return

# B

tes Rtn

tes / Cm

Scop

Lowercase 'L'. This get-only command reports back with the

value of the prior command received by the part. The

command also reports back any erroneous commands,

allowing the host device to verify that a command was

correctly received.

If this command is repeated, the second and subsequent

instances of 'l' will report back with 0x6C.

There is no put version of the command.

r 0x72 - R

ESET

EVICE

n/an/an/an/aGet

0x720x002n/aPut

Return

2nd B

tes / Cm

Scop

Section 3.11, p. 9

Lowercase 'R'. This put-only command hard-resets the part.

The command 0x72 must be followed by a null (0x00) within

100ms or the command will fail. The part must be in Put

mode for this command to work.

A reset occurs about 16ms after the echo byte 0x72 is

transmitted back to the host. The part will resume

communication and sensing in accordance with the timing

shown in Section 3.13.

If for some reason the part is unable to send back the echo

character 0x72, the command will fail.

There is no get version of the command.

V 0x56 - R

ETURN

ART

ERSION

0x00..0xFF11n/aGet

n/an/an/an/aPut

Returns# Bytes RtndBytes / CmdScope

Uppercase 'V'. This get-only command returns the part

version number.

There is no put version of the command.

W 0x57 - R

ETURN

ART

IGNATURE

0x1011n/aGet

n/an/an/an/aPut

Returns# Bytes RtndBytes / CmdScope

Uppercase 'W'. This get-only command returns the part

signature as follows:

0x10 (16 decimal)

There is no put version of this command.

Z 0x5A - E

NTER

LEEP

n/an/an/an/aGet

*0x5A, 0x5A0x002n/aPut

Returns2nd ByteBytes / CmdScope

Section 3.14, p. 9

Uppercase 'Z'. This put-only command forces the device to

enter sleep mode. The command 0x5A must be followed by a

null (0x00) within 100ms or the command will fail. The part

must be in Put mode for this command to work.

The command returns 0x5A immediately before going to

sleep, and a second 0x5A upon waking up.

If for some reason the device is unable to transmit the first

return ‘Z’ character back to the host, for example due to the

host not releasing the SS line, the part will completely reset

after about 2 seconds.

The part will reawaken after a logic low is detected for 10µs

on pin 11 (RST’ pin, see Section 3.11). The device then

sends a second ‘Z’ back to the host, and resumes from its

prior state before it went to sleep without the need for

recalibration. The device resumes in Get mode only.

There is no get version of the command.

^Q 0x11 - D

ATA

ATE

ELECTION

0x00..0x04n/a1n/aGet

0x110x00..0x042n/aPut

Return

2nd B

te Ran

tes / Cm

Scop

Section 4, p. 11

Ctrl-Q. This is a put-only command that sets the UART baud

rate and the SPI clock rate. All timings assume a 12MHz

oscillator. The part must be in Put mode for this command to

work.

SPI Settings -

The acceptable values of the operand for SPI use are:

0:93.75 kHz

1:187.5 kHz

2:750 kHz

3:3 MHz

These values define the maximum SPI clock rate in Master

mode (part originates the clock).

Note that when the part is receiving data, the host can send

to the device at rates up to 3MHz even if the rate setting of ^Q

is slower.

Refer to Sections 4.3 and 4.4 for SPI timing details.

New settings do not become effective until the device has

been powered off and back on again or after the reset (‘r’)

command.

UART Settings -

The acceptable values of the operand for UART use are:

0:9600 baud

1:14400 baud

2:19200 baud

3:38400 baud

4:57600 baud

There is no get version of this function.

Refer to Section 4.5for UART details.

New settings do not become effective until the device has

been powered off and back on again or after the reset (‘r’)

command.

www.qprox.com QT60161B / R1.03

^R 0x12 - O

SCILLOSCOPE

YNC

0x00, 0x01n/a11, 4, 16Get

0x120x00, 0x0121, 4, 16Put

Return

2nd B

te Ran

tes / Cm

Scop

Section 3.16, p. 11

Ctrl-R. In Put mode, controls the oscilloscope sync function

of Pin 43. The settings of this function are:

0:off {factory default}

1:on

When on, Pin 43 outputs a pulse that brackets the acquire

burst(s) for the keys targeted by scope. Without this it is

virtually impossible to view signals on an oscilloscope

corresponding to a specific key.

Pin 43 idles low and pulses high during a sync pulse.

^R is volatile, that is, it does not persist after a power down.

^W 0x17 - N

OISE

YNC

0x00, 0x01n/a1-Get

0x170x00, 0x012-Put

ReturnsByte 2 RangeBytes / CmdScope

Section 3.14, p. 9

Ctrl-W. In Put mode, sets whether the noise sync feature is

enabled or disabled. The part must be in Put mode for this

command to work.

The settings are:

0:off {factory default}

1:on

This function has global scope. The default value is 0 (off).

In Get mode this function returns the current setting of ^W.

The setting of ^W does not become effective until the device

has been powered off and back on again or after the reset

(‘r’) command has been issued.

www.qprox.com QT60161B / R1.03

5.6 Function Summary Table

0..0x0F1, 41, 4, 16Gget indication of all touched keysreport touches for group0x4BK

0..0xFF--Gget indication of first touched keyreport 1st key0x6Bk

0..0x0F1, 41, 4, 16Gget error bits for group error codes for group0x45E

0..0x0F11Gget error code for 1 keyerror code for 1 key0x65e

0..0xFF4, 164, 16Gget detection integrators for group Det integrator for group0x25%

0..0xFFFF8, 324, 16Gget References levels for group references for group0x22“

0..0xFF4, 164, 16Gget Reference-Signal for group delta signals for group0x21!

0..0xFFFF8, 324, 16Gget signal for group signals for group0x20<sp>

0..0x1F1-Gget device status of entire devicegeneral device status0x377

0..0xFF1-Gget eeprom checksum of entire eepromeeprom checksum0x366

0..0xFF11Gget detect integrator for 1 key Det Integrator for 1 key0x350

0..0xFFFF21Gget Reference level for 1 key reference for 1 key0x322

0..0xFF11Gget Reference-Signal for 1 key delta signal for 1 key0x311

0..0xFFFF21Gget signal strength for 1 key signal for 1 key0x300

Status Commands

undefined

0x790x00..0x032-Ptargets keys in a designated column, range 0..3Set column keys scope0x79y

undefined

0x780x00..0x032-Ptargets keys in a designated row, range 0..3Set row keys scope0x78x

undefined

0x531-Ptargets all keys in the matrixSet all keys scope0x53S

undefined

0x730x00..0x0F2-Ptargets a specific key in range 0..15Set one key scope0x73s

Sco

e Commands

Get

0x701-P

all subsequent Setup commands become 'Puts’

Put0x70p

Get

0x671-P

all subsequent Setup commands become 'Gets'

Get0x67g

Direction Commands

Return

range

Bytes

returned

ScopeReturns

Operand

Range

Bytes/PutScope Page

Default

setting

Get ModePut Mode

P/GDescriptionNameHexChar

27 www.qprox.com QT60161B / R1.03

240 (off)0x00, 0x01

110x10

0x00, 0x0121, 4, 16

P/Gadjacent key suppression feature; 1 = onKey suppression0x10^P

230 (off)0x00..0xFF1160x0F0x00..0xFF216

P/G

tolerable ne

ative reference deviation with respect to

Locked reference values, step 0.1%. Zero disables.

Neg error band0x0F^O

230 (off)0x00..0xFF1160x0E0x00..0xFF216

P/G

tolerable positive reference deviation with respect to

Locked reference values, step 0.1%. Zero disables.

Pos error band0x0E^N

230x020x02..0x0A1640x0D0x01..0x0A216

P/G

period of QT pulses, in microseconds

1, 2, 3, 4, 5, 6, 7, 8, 9, 10us

Intra-burst spacing0x0D^M

0x3C (9s)0x00..0xFF110x0C0x00..0xFF21, 8, 64

P/G

time required to trigger a recal from a detection, in 0.1s

increments. Zero disables recal.

0, 0.1, 0.2, 0.3, 0.5, 0.7, 1.0, 1.5, 2.0, 3.2,

4.5, 6, 9, 12.3, 17.5, 25.5 secs

Neg recal delay0x0C^L

230x0A (1s)0x00..0xFF110x0B0x00..0xFF21, 4, 16

P/G

time required to trigger a recal from a positive signal

excursion in 0.1s increments; zero disables recal.

0, 0.1, 0.2, 0.3, 0.5, 0.7, 1.0, 1.5, 2.0, 3.2,

4.5, 6, 9, 12.3, 17.5, 25.5 secs

Pos recal delay0x0B^K

220x030x00..0xFF110x0A0x00..0xFF21, 4, 16

P/G

number of detections required to register a touch,

counted in bursts of detection; zero disables a key.

0, 1, 2, 3, 5, 7, 10, 15, 20, 32,

45, 60, 90, 123, 175, 255 counts

Neg det int limit0x0A^J

220x0A (1s)0x01..0x64110x090x01..0x6421, 4, 16

P/G

rate of drift compensation for positive si

nal swin

0.1, 0.2, 0.3, 0.4, 0.6, 0.8, 1.0, 1.2, 1.5,

2.0, 2.5, 3.3, 4.5, 6.0, 7.5, 10 secs

Pos drift comp rate0x09^I

220x1E (3s)0x01..0x64110x080x01..0x6421, 4, 16

P/G

rate of drift compensation for ne

ative si

nal swin

0.1, 0.2, 0.3, 0.4, 0.6, 0.8, 1.0, 1.2, 1.5,

2.0, 2.5, 3.3, 4.5, 6.0, 7.5, 10 secs

Neg drift comp rate0x08^H

220 (500us)0x00..0x021160x070x00..0x02216

P/G

time from start of one burst to start of next burst

500us, 1ms, 2ms

Burst spacing0x07^G

210x0C0x01..0x40110x060x00..0x4021, 4, 16

P/G

sets number of QT cycles / burst; zero disables burst

0, 1, 2, 3, 4, 5, 7, 10, 12, 15, 20, 25, 30, 40, 50, 64

Burst length0x06^F

210x01 (25%)0x00..0x031160x040x00..0x03216

P/G

hysteresis for positive threshold

50%, 25%, 12.5%, 0%

Positive hysteresis0x04^D

210x01 (25%)0x00..0x031160x030x00..0x03216

P/G

hysteresis for negative threshold

50%, 25%, 12.5%, 0%

Negative hysteresis0x03^C

210x080x04..0x40110x020x04..0x4021, 4, 16

P/G

sensitivit

to positive si

nals for recalibration

4, 5, 6, 7, 8, 10, 12, 15, 17, 20, 25, 30, 35, 45, 55, 64

Positive threshold0x02^B

210x0C0x04..0x40110x010x04..0x4021, 4, 16

P/G

nal threshold; fewer counts = more sensitive

4, 5, 6, 7, 8, 10, 12, 15, 17, 20, 25, 30, 35, 45, 55, 64

Negative threshold0x01^A

Setu

Commands

Return

range

Bytes

returned

ScopeReturns

Operand

Range

Bytes/PutScope Page

Default

setting

Get ModePut Mode

P/GDescriptionNameHexChar

28 www.qprox.com QT60161B / R1.03

0 (off)0x00, 0x011-0x170x00, 0x012-G/P

noise sync enable; 1 = on

device must be reset to take effect

Noise sync0x17^W

0 (off)0x00, 0x011-0x120x00, 0x0121, 4, 64P/G

oscilloscope sync control. 1 = on.

feature is volatile - does not survive reset

Scope sync0x12^R

0 (93.75k,

9600)

0x00..0x041-0x110x00..0x042-P/G

sets the Master mode SPI clock rate and UART rate;

reset via ‘r’ command or hard reset to take effect

SPI: 93.75kHz, 187.5kHz, 750kHz, 3MHz

UART: 9.6k, 14.4k, 19.2k, 38.4k, 57.6k

Data rate0x11^Q

0x5A,

0x5A

0x002-P

force device into Sleep mode. ‘Z’ must be followed b

null within 100ms. 0x5A returned before and after

entering Sleep

Sleep0x5AZ

0x101-Greturns part signature numberSignature0x57W

0x00..0xFF1-Greturns part version numberVersion0x56V

0x720x002-P

hard reset the device. ‘r’ must be followed by a null within

100ms.

Reset device0x72r

0x00..0xFF1-Gsend back last command byte receivedReturn last command0x6Cl

0x6211, 4, 16P

fully recalibrate keys;

return byte is sent prior to calibration

Recal keys0x62b

0x4C0x00216P

locks reference levels into eeprom for future boundar

checks. ‘L’ must be followed by 0x00 (null) 100ms after

the command byte

Lock references0x4CL

0x00..0xFF1-Greturns checksum of internal eepromEeprom checksum0x366

ervisor

Commands

Return

range

Bytes

returned

ScopeReturns

Operand

Range

Bytes/PutScope Page

Default

setting

Get ModePut Mode

P/GDescriptionNameHexChar

29 www.qprox.com QT60161B / R1.03

5.8 Erratta / Notes

4 April 2003 - The QT60xx5 version 1.05 datasheet erroneously showed negative recalibration timeouts in the range from

1..255 seconds. The correct range is 0.1..25.5 seconds. From datasheet version 1.06 on, this document change has been

made. The devices themselves are not affected.

5.7 Timing Limitations

The device requires processing time between bursts, as well

as time to handle communications with the host. With short

burst spacings, long burst lengths, and long intra-burst pulse

spacings, the device can simply run out of available

processing time. When this happens, burst timing and host

communications slow down and become erratic.

It is important that burst spacings be verified on an

oscilloscope with an actual keymatrix during development to

be certain that the device timings are preserved and are

constant. If not, the burst length and/or pulse spacing should

be reduced.

www.qprox.com QT60161B / R1.03

Table 5-2 Permissible Burst Lengths (BL’s)

Cs = 4.7nF, Cx = 5pF, Rs = 180K; 100µs ramp time

642,000642,000642,000642,000

401,000401,000501,000501,000

20500205002550030500

Max BL

Burst

Spacing

Max BL

Burst

Spacing

Max BL

Burst

Spacing

Max BL

Spacing

Pulse Spacing = 10µsPulse Spacing = 9µsPulse Spacing = 8µsPulse Spacing = 7µs

642,000642,000642,000642,000642,000

641,000641,000641,000641,000641,000

3050040500505006450064500

Max BL

Burst

Spacing

Max BL

Burst

Spacing

Max BL

Burst

Spacing

Max BL

Burst

Spacing

Max BL

Burst

Spacing

Pulse Spacin

= 6µsPulse Spacin

= 5µsPulse Spacin

= 4µsPulse Spacin

= 3µsPulse Spacin

= 2µs

6 Electrical Specifications

6.1 Absolute Maximum Specifications

Operating temp....................................................................... -40

C to +105

Storage temp......................................................................... -55

C to +125

..................................................................................... -0.5 to +5.5V

Max continuous pin current, any control or drive pin.................................................±10mA

Short circuit duration to ground, any pin............................................................infinite

Short circuit duration to V

, any pin.............................................................. infinite

Voltage forced onto any pin..................................................... -0.6V to (Vdd + 0.6) Volts

Frequency of operation......................................................................... 16MHz

Eeprom maximum writes............................................................ 100,000 write cycles

6.2 Recommended operating conditions

................................................................................... +4.75 to 5.25V

Supply ripple+noise.......................................................................5mV p-p max

Cx transverse load capacitance per key.........................................................0 to 20pF

Fosc oscillator frequency.................................................................. 12MHz +/-2%

6.3 DC Specifications

Vdd = 5.0V, Cs = 4.7nF, Freq = 12MHz, Ta = recommended range, unless otherwise noted

Drdy, SS’ pinskohms12035Pullup resistorsR

bits

1610

Acquisition resolutionA

µA±1Input leakage currentI

1mA sourceVVdd-0.7High output voltageV

4mA sinkV0.6Low output voltageV

V2.2High input logic levelV

V0.8Low input logic levelV

Not including external componentsµA

Supply current, sleepI

DDS

Not including external componentsmA25Supply current, runningI

DDR

Notes

UnitsMaxTypMinDescription

Paramete

6.4 Protocol Timing

µS2,00015Multi-byte return spacingT

µS1,0001Tdr delay from responseT

µS100Parallel port response delayT

Notes

UnitsMaxTypMinDescription

Parameter

www.qprox.com QT60161B / R1.03

6.5 Maximum Drdy Response Delays

... with adjacent key suppression disabled:

1ms1ms1.5ms

All other commands

1ms2ms1.5ms

Get key errors (E), Get keys pushed (K)

1.1ms2ms2ms

Calibrate command (all keys)

65ms65ms65ms

Lock reference Level (L)

65ms65ms65ms

Setup - put (affect 16 keys)

20ms20ms20ms

Setup - put (affect 4 keys)

10ms10ms10ms

Setup - put (affect 1 key)

2ms1ms500µsFunction Type

Burst Spacing

... with adjacent key suppression enabled:

1.1ms2ms1.5ms

All other commands

1.1ms2ms2ms

Get key errors (E), Get keys pushed (K)

1.2ms2ms2.5ms

Calibrate command (all keys)

65ms65ms65ms

Lock reference Level (L)

65ms65ms65ms

Setup - put (affect 16 keys)

20ms20ms20ms

Setup - put (affect 4 keys)

10ms10ms10ms

Setup - put (affect 1 key)

2ms1ms500µsFunction Type

Burst Spacing

Preliminary Data: All specifications subject to change.

www.qprox.com QT60161B / R1.03

7 Mechanical

7.1 Dimensions

7.2 Marking

www.qprox.com QT60161B / R1.03

12 14 16 18 2220

15 17 19 2113

44 42 40 38 36 34

43 41 3739 35

SYMBOL

Millimeters Inches

Min Max Notes Min Max Notes

12.2111.75 0.458 0.478

0.09 0.20 0.003 0.008

0.45

0.05

0.75

0.15

1.20

0.018

0.002

0.030

0.006

0.047

0.80

0.30

BSC

8.00

0.80

0.45

0.031

0.012

BSC

0.315

0.031

0.018

9.90 10.10 0.386 0.394

o07 07

BSC BSC

SQSQ

Package Type: 44 Pin TQFP

8.00 0.315

QT60161B-AQT60161B-AS-40

C to +105

MarkingTQFP Part NumberT

8 Index

adc, 8

adjacent key suppression, 6, 7, 12, 24, 28, 32

alert output

led, 10, 11

application assistance, 4

block diagram, 5

boundary limits, 19, 23, 29

burst length, 4, 7, 8, 9, 17, 21, 28, 30

burst spacing, 8, 9, 14, 22, 28, 30, 32

burst timing, 15, 30

calibration

recalibration, 5, 6, 7, 9, 10, 17, 19, 21, 23, 24, 29

circuit model, 7

cs, 5, 8, 9

delta signals, 19, 27

detection integrator, 5, 6, 8, 18

direction commands, 17

drdy’, 12

drift compensation, 5, 6, 11, 17, 21, 22, 23

dwell, 7, 9

echo, 12, 13, 15, 21, 24

eeprom checksum, 18, 24

electrostatic shield, 11

emi, 11, 23

rfi, 8, 9, 21

error code, 4, 11, 16, 17, 19, 20, 21, 23

error guardbanding, 23

esd protection, 8, 9, 11

field flow, 4, 8

function summary table, 27

get command, 17

ground plane, 11

hysteresis, 5, 21, 22

intra-burst pulse spacing, 9, 23

key design, 4

key numbering convention, 18

key reporting, 20

led

alert output, 10, 11

lock reference levels, 6, 14, 23, 24

master mode, 12, 13

master-slave mode, 4, 12, 13

miso, 12, 13

mosi, 9, 12, 13

negative detect integrator, 22

negative detect threshold, 21

negative drift compensation, 22

negative hysteresis, 5

negative recalibration delay, 6, 23

negative reference error band, 23

negative threshold, 5, 7, 8, 21, 22, 23

noise, 11, 12

noise filter, 22. see also emi

oscillator, 7, 9, 10, 12, 14, 25

oscilloscope sync, 11, 26

pcb layout, 4, 11

positive detect threshold, 21

positive recalibration delay, 6, 7, 23

positive reference error band, 23

positive threshold, 5, 6, 7, 21, 23

power supply, 11

pulse spacing, 9, 23

put command, 17

qmbtn, 4, 10, 11

recalibrate keys (command), 24

recalibration

calibration, 5, 6, 7, 9, 10, 17, 19, 21, 23, 24, 29

reset, 7, 9, 10, 11, 17, 25, 26

resonator, 7, 9. see also oscillator

return last command, 25

www.qprox.com QT60161B / R1.03

return part signature, 25

rfi

emi, 8, 9, 21

slave mode, 13

sleep mode, 10

spi, 12, 15

spi noise problems, 11

tcm, 12, 15

water films, 24

x-drives, 7, 8

www.qprox.com QT60161B / R1.03

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The specifications set out in this document are subject to change without notice. All products sold and services supplied by QRG are subject

to our Terms and Conditions of sale and supply of services which are available online at www.qprox.com and are supplied with every order

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