ET2020/EFA - Oxley Developments Co., Ltd.

ET2020/EFA

www.oxleygroup.com/eti

ODCSM40539/2/2005

Oxley Developments Company Ltd

Email: sales@oxley.co.uk

Tel: +44 (0)1229 483226

Oxley Group Australia Pty Ltd

Email: sales@oxleygroup.com

Tel +61 (0) 2 9967 9488

Oxley Inc.

Email: sales@oxleyinc.com

Tel: +1 (203) 488 1033

Elapsed Time Indicator ET2020/EFA

Features

• EEPROM non-volatile memory.

• 10 years data retention.

• Low power, 10 mW typical.

• Serial and parallel outputs.

• Microprocessor compatible.

• Non-volatile text storage and recall.

• Military specifications.

For ordering information see page 22.

Construction

The 18 pin ceramic dual-in-line package is assembled

using thick film chip hybrid technology, ensuring

suitability for military, avionic, and industrial applications

where severe environmental conditions maybe

encountered.

Note: The Test pin is provided for factory purposes

only and should be left unconnected.

910

VAUX

Output Select

Request Time

Count

Data Valid

Test

VSS

VCC

Pin 18

Pin 1

16.2 mm

(0.638") max

5 mm (0.197") nom

3 mm (0.600") nom

30.4 mm (1.197") nom

0.56 mm

(0.022") max

Pitch 2.54 mm

(0.100")

15.24 mm

(0.600") CRS

0.25 mm

(0.010") nom

ET2020/EFA

16 www.oxleygroup.com/eti

ODCSM40539/2/2005

Oxley Developments Company Ltd

Email: sales@oxley.co.uk

Tel: +44 (0)1229 483226

Oxley Group Australia Pty Ltd

Email: sales@oxleygroup.com

Tel +61 (0) 2 9967 9488

Oxley Inc.

Email: sales@oxleyinc.com

Tel: +1 (203) 488 1033

Application Circuit Diagrams

Typical application ODCSM40539/2/2005circuit diagrams are shown below for serial and parallel

interrogation modes. The internal timer is activated whenever the 5 V power supply is applied. No

additional timing control circuitry is required. The total elapsed time is accumulated in the internal

non-volatile memory for interrogation through either the serial or parallel interfaces.

Serial Mode

Parallel Mode

VAUX

Output Select

Request Time

Count

Data Valid

Test

VSS

VCC

RS 232

Level

Shifter

0 Volts

ET2020/EFA

5 Volt Equipment Supply

VAUX

Output Select

Request Time

Count

Data Valid

Test

VSS

VCC

0 Volts

ET2020/EFA

5 Volt Equipment Supply

Data Valid

Request

Time

External

Control

Circuitry

8 bit - Tristate

Data Bus

ET2020/EFA

www.oxleygroup.com/eti

ODCSM40539/2/2005

Oxley Developments Company Ltd

Email: sales@oxley.co.uk

Tel: +44 (0)1229 483226

Oxley Group Australia Pty Ltd

Email: sales@oxleygroup.com

Tel +61 (0) 2 9967 9488

Oxley Inc.

Email: sales@oxleyinc.com

Tel: +1 (203) 488 1033

Power Supply

A single 5 Volt power supply, Vcc is required for operation. A separate power supply input Vaux is also

provided for energisation from a second power source. A blocking diode is internally connected to prevent

current from Vaux powering parent equipment connected to Vcc. This provides cold read facilities during

failure of parent equipment or when it is powered down.

Interrogation

The ETI can be interrogated in either serial or parallel format. The OUTPUT SELECT (OS) input is used

for selection of interrogation mode.

Serial Data (Output Select = 0)

Serial data transfer uses two pins, Rx (receive data), and Tx (transmit data). Together with a signal

common, these lines constitute a 3 wire serial communication interface utilising a standard non-return to

zero (NRZ), data format. Direct interface can be made with integrated circuit UART devices. The signals

can also be level shifted to conform to RS232 requirements.

The Rx and Tx signals must meet the following requirements:-

1A High level indicates logic 1 (5 V) and a low level indicates logic 0 (0 V).

2The Rx input must be in a high state prior to reception of data.

3A start bit, (logic 0), is transmitted/received indicating the start of a message.

4Bytes of data are transmitted/received least significant bit first.

5A stop bit, (logic 1), in the 10th bit position indicates transmission/reception of a byte is complete.

6Baud rate: 9600 b/s

Data bits: 8

Start bits: 1

Stop bits: 1

Parity: None

To initiate transmission of serial elapsed time/pulse count data a unique two character ASCII command

“ET” must be received at the Rx input. Following reception of a valid “ET” command the ETI will output the

elapsed time message on the Tx output. If an invalid command is received an ASCII carriage return

character, (0D hex), is transmitted.

ET2020/EFA

18 www.oxleygroup.com/eti

ODCSM40539/2/2005

Oxley Developments Company Ltd

Email: sales@oxley.co.uk

Tel: +44 (0)1229 483226

Oxley Group Australia Pty Ltd

Email: sales@oxleygroup.com

Tel +61 (0) 2 9967 9488

Oxley Inc.

Email: sales@oxleyinc.com

Tel: +1 (203) 488 1033

Serial Elapsed Time Interrogation

Bytes 1 and 12 are ASCII carriage return characters. Bytes 2 to 9 represent the elapsed time reading and

are ASCII characters. Byte 2 is the most significant digit. Byte 7 is always “.” and byte 11 “H” denoting units

of hours. Elapsed time measurement is suspended for typically 300 ms during serial data output.

Parallel Data (Output Select = 1)

Parallel elapsed time/pulse count interrogation is initiated by holding the REQUEST TIME input at logic 0

for time tRT or until the positive edge of DV(1). The elapsed time/pulse count time information then appears

sequentially in 3 bytes on outputs D0-D7. Data is synchronised with pulses which appear on the DATA

VALID (DV) output. Each byte represents a 2 digit BCD number. Outputs D7-D4 represent the most

significant digit, outputs D3-D0 represent the least significant digit. D0-D7 are tri state outputs suitable for

direct connection onto a high impedance data bus.

Parallel Text Interrogation

Parallel text interrogation is initiated by holding the REQUEST TIME input at logic 0 for the time tRTT or

until the positive edge of DV(4). Following the 3 bytes of elapsed time/pulse count information, the ASCII

text appears on outputs D0-D7 synchronised with DATA VALID pulses DV(4) to DV(53). To request

elapsed time information only, the REQUEST TIME pulse width should not exceed tRT max. Elapsed time

measurement is suspended for typically 300 ms during parallel data output.

BYTE 123456789101112

CHARACTERcr00000. 00 Hcr

HEX 0D30303030302E303020480D

VCC

“E” “T”

“CR” “H” “CR”

900 ms min 6 ms max

1 ms min

Byte

ET2020/EFA

www.oxleygroup.com/eti

ODCSM40539/2/2005

Oxley Developments Company Ltd

Email: sales@oxley.co.uk

Tel: +44 (0)1229 483226

Oxley Group Australia Pty Ltd

Email: sales@oxleygroup.com

Tel +61 (0) 2 9967 9488

Oxley Inc.

Email: sales@oxleyinc.com

Tel: +1 (203) 488 1033

BCD Parallel Output

During DV(1) the digits represent HOURS x 103 and HOURS x 102.

During DV(2) the digits represent HOURS x 101 and HOURS x 100.

During DV(3) the digits represent HOURS x 10-1 and HOURS x 10-2.

Parameter Description Min Max Units

tIInitialisation time 900 ms

tRT Request time pulse width for time information only 6 12 ms

tRTT Request time pulse width for time & text information 16 ms

tSDV Time to set up 1st data valid 6 ms

tDV Data valid pulse width 90 110 µs

tPDV Period of data valid 4.99 5.01 ms

tOT Total bus active time 264 ms

tOET Total bus active time, elapsed time

only output

15 ms

tZDV Time from end of Z state to 1st DV 175 typical µs

tDS Data set up time 90 typical µs

tRTP Request time repetition period 300 ms

HIGH IMPEDANCE

READING = 1234.56 "T" "E" "X" "T" "$"

HIGH IMPEDANCE

Vcc

ZDV

RTP

OET

RTT

PDV

SDV

DV(1) DV(2) DV(3) DV(4) DV(5) DV(6) DV(7) DV(53)

ET2020/EFA

20 www.oxleygroup.com/eti

ODCSM40539/2/2005

Oxley Developments Company Ltd

Email: sales@oxley.co.uk

Tel: +44 (0)1229 483226

Oxley Group Australia Pty Ltd

Email: sales@oxleygroup.com

Tel +61 (0) 2 9967 9488

Oxley Inc.

Email: sales@oxleyinc.com

Tel: +1 (203) 488 1033

User Programmable Text

50 bytes of EEPROM are provided for user entry and storage of 50 characters of text information. The text

may record, for example, maintenance and warranty status of parent equipment. Text may be rewritten as

often as required and can be read by both serial and parallel outputs. Text can only be entered serially.

Text Entry

Text entry can only be made whilst in serial mode and is initiated by detection of the ASCII “IX”: command

at the Rx input. Up to 50 ASCII text characters should then be input, terminated either by a carriage return

or by entry of the 50th character. Text entered will overwrite previously stored text.

Serial Text Input

Serial Text Interrogation

Serial text interrogation is achieved by using the ASCII “OX” command.Serial Text Output

VCC

“I” “X”

“CR”

900 ms min 5 ms min

1 ms min

Text

0.1 ms min 0.2 ms typical

VCC

“O” “X”

“CR”

900 ms min 6 ms max

1 ms min

Text

0.1 ms typical

“CR”

ET2020/EFA

www.oxleygroup.com/eti

ODCSM40539/2/2005

Oxley Developments Company Ltd

Email: sales@oxley.co.uk

Tel: +44 (0)1229 483226

Oxley Group Australia Pty Ltd

Email: sales@oxleygroup.com

Tel +61 (0) 2 9967 9488

Oxley Inc.

Email: sales@oxleyinc.com

Tel: +1 (203) 488 1033

Typical Drive Current Graph

7.0

6.0

5.0

4.0

3.0

2.0

1.0

ID (mA)

0.5 1.0 1.5 2.0

VCC - VOH (volts)

ET2020/EFA

22 www.oxleygroup.com/eti

ODCSM40539/2/2005

Oxley Developments Company Ltd

Email: sales@oxley.co.uk

Tel: +44 (0)1229 483226

Oxley Group Australia Pty Ltd

Email: sales@oxleygroup.com

Tel +61 (0) 2 9967 9488

Oxley Inc.

Email: sales@oxleyinc.com

Tel: +1 (203) 488 1033

Characteristics

Ordering Information

When ordering please state Type No. and quantity required.

Operating temperature range -55°C to 125°C

Storage temperature range -55°C to 125°C

Supply voltage, VCC 4.5 to 5.5 V d.c.

Supply voltage, VAUX 4.0 to 5.5 V d.c.

Supply current 2 mA typical, 4 mA max.

Timing resolution 0.01 hours

Timing accuracy ± 0.1%

Capacity (PARALLEL MODE) 104 hours /106 pulses

Capacity (SERIAL MODE) 105 hours /107 pulses

VOH, Output logic 1 VCC-1 to VCC Iload <1ma

VOL, Output logic 0 VSS to 0.4V

VIH, Input logic 1 0.8 x VCC to VCC

VIL, Input logic 0 VSS to 0.2 x VCC

IZ, High Z leakage current ± 10 µA

Elapsed Time Indicator Order Code ET2020/EFA