19-4062; Rev 0; 2/08 MAX5432 Evaluation Kit The MAX5432 evaluation kit (EV kit) is an assembled and tested printed-circuit board (PCB) that evaluates the MAX5432 IC. The MAX5432 is a 32-tap, 50k, nonvolatile, linear digital potentiometer communicating over I 2 C. The MAX5432 features an internal nonvolatile EEPROM used to store the potentiometer's wiper position for initialization during power-up. The EEPROM is programmed through the I2C-compatible serial interface, communicating at data rates up to 400kbps. The I2C signals can be transmitted through an on-board USB interface circuit using a computer or a user-supplied I2C bus along with the PCB interfacing pads. The EV kit also features Windows 2000/XP/Vista (R) compatible software that provides a professional user interface for exercising the MAX5432's features. The program is menu driven and offers a graphical user interface (GUI) complete with buttons, track bars, and pulldown menus. The EV kit is powered from a 3.3V source generated from the EV kit's USB interface circuit, or an external 2.7V to 5.25V DC power supply. The MAX5432 IC is available in two versions, the MAX5432LETA and the MAX5432META; each version has two selectable I2C addresses. The MAX5432 EV kit is shipped with a MAX5432LETA IC installed. The EV kit can also evaluate the MAX5433 (100k) after IC replacement (U1). The MAX5433 is also available in two versions; each version has four unique I2C addresses. Features Power-On Recall of Wiper Position from Nonvolatile Memory 2.7V to 5.25V Single-Supply Operation Configurable Device Address On-Board USB Interface Circuit for I2CCompatible Signals USB-PC Connection and Powered (Cable Included) PCB Pads for User-Supplied I2C-Compatible Signals PCB Pads for Potentiometer Signals L, W, H Proven USB-Compatible PCB Layout Evaluates the MAX5432LETA, MAX5432META, MAX5433LETA, and MAX5433META in a 3mm x 3mm 8-pin TDFN package Windows 2000/XP/Vista (32-Bit)-Compatible Software Fully Assembled and Tested Ordering Information PART TYPE MAX5432EVKIT+ EV Kit +Denotes lead-free and RoHS-compliant. Windows Vista is a registered trademark of Microsoft Corp. DESIGNATION C1, C3-C10, C17, C26 C2, C13, C15 C11, C12 C14, C16, C21-C25 QTY DESCRIPTION 11 0.1F 10%, 16V X7R ceramic capacitors (0603) Murata GRM188R71C104K TDK C1608X7R1C104K 3 10F 20%, 6.3V X5R ceramic capacitors (0805) Murata GRM21BR60J106M TDK C2012X5R0J106M 2 10pF 5%, 50V C0G ceramic capacitors (0603) Murata GRM1885C1H100J TDK C1608C0G1H100J 7 1F 10%, 10V X5R ceramic capacitors (0603) Murata GRM188R61A105K TDK C1608X5R1A105K Component List DESIGNATION QTY DESCRIPTION 2 22pF 5%, 50V C0G ceramic capacitors (0603) Murata GRM1885C1H220J TDK C1608C0G1H220J C20 1 3300pF 10%, 50V X7R ceramic capacitor (0603) Murata GRM188R71H332K TDK C1608X7R1H332K D1 1 Green LED (0603) Panasonic LNJ314G8TRA FB1 0 Not installed, ferrite-bead inductor (0603) C18, C19 JU1 1 3-pin header JU2-JU6 5 2-pin headers P1 1 USB series type-B right-angle male receptacle ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim's website at www.maxim-ic.com. 1 Evaluates: MAX5432/MAX5433 General Description Evaluates: MAX5432/MAX5433 MAX5432 Evaluation Kit Component List (continued) DESIGNATION QTY DESIGNATION QTY R1 1 0 5% resistor (0603) Y1 1 16MHz crystal R2 1 220 5% resistor (0603) Y2 1 6MHz crystal R3 1 10k 5% resistor (0603) -- 6 Shunts R4 1 2.2k 5% resistor (0603) -- 1 USB high-speed A-to-B cable, 6ft R5 1 1.5k 5% resistor (0603) -- 1 PCB: MAX5432 Evaluation Kit+ R6, R7 2 27 5% resistors (0603) R8-R11 4 2k 5% resistors (0603) R12 1 100k 5% resistor (0603) U1 1 Nonvolatile linear taper digital potentiometer (8-pin TDFN-EP*) Maxim MAX5432LETA+ 1 32-bit microcontroller (68-pin QFN-EP*, 10mm x 10mm) Maxim MAXQ2000-RAX+ U2 DESCRIPTION U3 1 93C46 type 3-wire EEPROM 16-bit architecture (8-pin SO) U4 1 UART-to-USB converter (32-pin TQFP, 7mm x 7mm) 1 3.3V regulator (5-pin SC70) Maxim MAX8511EXK33+ U5 U6 U7, U8 1 2.5V regulator (5-pin SC70) Maxim MAX8511EXK25+ 2 Low-voltage level translators (10-pin MAX(R)) Maxim MAX1840EUB+ MAX is a registered trademark of Maxim Integrated Products, Inc. Quick Start Required Equipment Before beginning, the following equipment is needed: * * * MAX5432 EV kit (USB cable included) A user-supplied Windows 2000/XP/Vista-compatible PC with a spare USB port Ohmmeter Note: In the following sections, software-related items are identified by bolding. Text in bold refers to items directly from the EV kit software. Text in bold and underlined refers to items from the Windows operating system. Procedure The MAX5432 EV kit is fully assembled and tested. Follow the steps below to verify board operation: 1) Visit www.maxim-ic.com/evkitsoftware to download the latest version of the EV kit software, 5432Rxx.ZIP. 2 DESCRIPTION *EP = Exposed pad. Component Suppliers SUPPLIER PHONE WEBSITE Murata Mfg. Co., Ltd. 770-436-1300 www.murata.com Panasonic Corp. 800-344-2112 www.panasonic.com TDK Corp. 847-803-6100 www.component.tdk.com Note: Indicate that you are using the MAX5432 or MAX5433 when contacting these component suppliers. MAX5432 EV Kit Files FILE DESCRIPTION INSTALL.EXE Installs the EV kit files on the computer MAX5432.EXE Application program FTD2XX.INF USB driver file UNINST.INI Uninstalls the EV kit software USB_Driver_Help.PDF USB driver installation help file Note: The MAX5432 EV kit software can be downloaded from www.maxim-ic.com/evkitsoftware. Save the EV kit software to a temporary folder and uncompress the ZIP file. 2) Install the EV kit software on the computer by running the INSTALL.EXE program inside the temporary folder. The program files are copied and icons are created in the Windows Start | Programs menu. 3) Verify that a shunt is installed on pins 1-2 of jumper JU1. This configures the MAX5432 IC's VDD to operate from the 3.3V generated by the USB interface circuit. 4) Verify that a shunt is installed on jumpers JU2 and JU3. This configures the I2C input pins to receive signals from the USB interface circuit. 5) Verify that a shunt is installed on jumper JU4. This configures the MAX5432LETA I2C address to 0x50. 6) Verify that no shunts are installed on jumpers JU5 and JU6, the L PCB pad is not connected to GND, and the H PCB pad is not connected to the W PCB pad. _______________________________________________________________________________________ MAX5432 Evaluation Kit ware main window appears in the upper-left corner of the window. 12) The MAX5432 EV kit is ready for additional testing. See the Detailed Description of Software section for more information on the software features. Detailed Description of Software In the following sections, text in bold refers to items directly from the EV kit software. Graphical User Interface (GUI) The MAX5432 EV kit software GUI (Figure 1) is a Windows program that provides a convenient means to control the MAX5432. Use the mouse or press the TAB key to navigate through the GUI controls. The correct I 2 C write operation is generated to update the MAX5432 internal memory registers when any of these controls are executed. The software divides EV kit functions into logical blocks. The Interface group box indicates the EV kit's Status, Device Address, I2C Bus Speed, the last write operation Command Sent, and Data Sent indicators. This data is used to confirm proper device operation. The Potentiometer Control group box changes the wiper position, stores the wiper position from the volatile memory to the nonvolatile memory, and recalls the wiper position from the nonvolatile memory to the Figure 1. MAX5432 Evaluation Kit Software Main Window _______________________________________________________________________________________ 3 Evaluates: MAX5432/MAX5433 7) Connect the ohmmeter across the W and L PCB pads. 8) Connect the included USB cable from the PC to the MAX5432 EV kit. A Building Driver Database window pops up in addition to a New Hardware Found message when installing the USB driver for the first time. If a window similar to the one described above does not appear after 30s, remove the USB cable from the board and reconnect it. Administrator privileges are required to install the USB device driver on Windows 2000/XP/Vista. 9) Follow the directions of the Add New Hardware Wizard to install the USB device driver. Choose the Search for the best driver for your device option. Specify the location of the device driver to be C:\Program Files\MAX5432 (default installation directory) using the Browse button. During device driver installation, Windows may show a warning message indicating that the device driver Maxim uses does not contain a digital signature. This is not an error condition and it is safe to proceed with installation. Refer to the USB_Driver_Help.PDF document for additional information. 10) Start the MAX5432 EV kit software by opening its icon in the Start | Programs menu. 11) Observe as the program automatically detects the address of the MAX5432 and starts the main program. After successful connection, the EV kit soft- Evaluates: MAX5432/MAX5433 MAX5432 Evaluation Kit volatile memory. The bottom-left status bar of the main window provides the USB interface circuit communication status. The bottom-right status bar indicates the presence or absence of the MAX5432 IC. The Factory Default button programs the volatile and nonvolatile memory of the potentiometer to midscale position. Software Startup Upon starting the program, the MAX5432 EV kit software automatically searches for the USB interfacecircuit connection, and then for the device address. The MAX5432 EV kit enters the normal operating mode when the USB connection is detected and has found the device address. The nonvolatile memory wiper position is then transferred to the volatile memory. Since the MAX5432 does not have read capability, all the spin boxes are set to question marks (??) and the track bar is set to midscale. If the USB connection is not detected, the software prompts the user to retry, exit the program, or enter the demo mode. Demo Mode The MAX5432 EV kit software can enter the demo mode, when the USB connection is not detected, by pressing the Cancel button on the MAX5432 Evaluation Kit Interface Circuit popup window (Figure 2). The software can also enter the demo mode at any time using the Options | Demo Mode pulldown menu item in the main window. When in demo mode, all software communication to the EV kit circuit is disabled; however, most of the software GUI is functional. Demo mode allows the user to evaluate the software without hardware connectivity. To exit demo mode, select Options | Demo Mode from the pulldown menu. Wiper Position The Wiper Position track bar in the Potentiometer Control group box can be used to change the wiper position between the H and L end points. Use the computer mouse or the keyboard UP and DOWN arrow keys to move the wiper position between the 32 position points. The wiper position can also be changed by entering a numerical value between 0 and 31 into the H-W Volatile or L-W Volatile spin boxes, or by selecting the up/down buttons of these spin boxes. A change in the Wiper Position track bar, or HW Volatile/L-W Volatile spin boxes will write to the volatile memory and the wiper position is updated with the data sent. The data in the nonvolatile memory remains unchanged. The wiper position is shown in the H-W Volatile and L-W Volatile spin boxes. The H-W Volatile spin box shows the wiper position with respect to the H end point and the L-W Volatile spin box shows the wiper position with respect to the L end point. During EV kit power-up, the wiper position data in the nonvolatile memory is transferred to the volatile memory and the position of the wiper is updated. The H-W Volatile, L-W Volatile, H-W Nonvolatile, and L-W Nonvolatile spin boxes display question marks (??) after initializing the EV kit software because the MAX5432 does not transmit data to the master. Nonvolatile Programming The H-W Nonvolatile and L-W Nonvolatile spin boxes in the Potentiometer Control group box can be used to program the nonvolatile memory of the digital potentiometers. The nonvolatile memory can be changed by entering a numerical value between 0 and 31 into the H-W Nonvolatile or L-W Nonvolatile spin boxes. The H-W Nonvolatile spin box shows the wiper position with respect to the H end point and the L-W Nonvolatile spin box shows the wiper position with respect to the L end point. When writing to the nonvolatile memory, the volatile memory and wiper position remain unchanged. Volatile/Nonvolatile Data Transferring The Potentiometer Control group box contains the Store and Recall buttons that are used to transfer data from the volatile memory to the nonvolatile memory and vice versa. When the Store button is pressed, the data present in the volatile memory is transferred to the nonvolatile memory. Figure 2. MAX5432 Evaluation Kit Interface Circuit Popup Window 4 _______________________________________________________________________________________ MAX5432 Evaluation Kit Status Indicator The Status indicator in the Interface group box displays EV Kit Operational when the MAX5432 EV kit enters the normal operating mode after the USB connection is detected and the device address is found. When USB connection is not detected or device is not found, or when the software enters the demo mode, the Status indicator displays Device not found. I2C Bus Speed Indicator Factory Default I 2C Pressing the Factory Default button resets the wiper position in the MAX5432 volatile and nonvolatile memory to the factory-default position. The factory-default wiper position is the midscale position. The Bus Speed indicator in the Interface group box displays the I2C bus speed. The I2C bus speed is set to 400kbps by the MAX5432 EV kit software. Device Address The Command Sent indicator in the Interface group box displays the last command sent from the master (software) to the MAX5432. There are four commands available in the MAX5432 IC, as described in Table 1. The Interface group box contains a Device Address combo box that stores up to four device addresses found by the MAX5432 EV kit software. The MAX5432 EV kit software automatically searches for the MAX5432 during startup using the four possible addresses shown in Table 4. Each of the four unique device addresses found by the software will be stored in the Device Address combo box. Use the Device Address combo box to select between different devices that share the same bus. If no device is found, the Device Address is set to Auto Detect. Select the Auto Detect option from the Device Address combo box to search for new additional device addresses. A maximum of four MAX5432/MAX5433 devices can share the same I2C bus. Command Sent Indicator Data Sent Indicator The Data Sent indicator in the Interface group box displays the last data sent from the master (software) to the MAX5432. The MAX5432 IC uses the first 5 bits (MSBs, D7-D3) of the data byte to set the wiper position. The last 3 bits (D2, D1, and D0) are "Don't Care's." Refer to the MAX5432/MAX5433 IC data sheet for additional information. Table 1. MAX5432 I2C Command MAX5432 REGISTER VREG COMMAND DESCRIPTION EV KIT SOFTWARE CONTROL 0x11 I2C data is written to VREG Wiper position updates with I2C data No change to NVREG H-W Volatile L-W Volatile H-W Nonvolatile L-W Nonvolatile BINARY HEX 00010001 NVREG 00100001 0x21 I2C data is written to NVREG No change to wiper position No change to VREG VREGxNVREG 01010001 0x51 Copy VREG to NVREG No change to wiper position No change to VREG Store NVREGxVREG 01100001 0x61 Copy NVREG to VREG Wiper position updates with NVREG No change to NVREG Recall _______________________________________________________________________________________ 5 Evaluates: MAX5432/MAX5433 When the Recall button is pressed, the data present in the nonvolatile memory is transferred to the volatile memory and the wiper position is updated. When either Store or Recall button is pressed, the EV kit software Data Sent indicator shows the last known data that is being transferred. These commands do not send any data to the device because the commands transferred data already contained in the volatile or nonvolatile memory. Evaluates: MAX5432/MAX5433 MAX5432 Evaluation Kit Keyboard Navigation Press the TAB key to select each GUI control. The selected control is indicated by a dotted outline. Using SHIFT+TAB moves the selection to the previously selected control. Buttons respond to the keyboard's SPACE bar. Some controls respond to the keyboard UP and DOWN arrow keys. Activate the program's menu bar by pressing the F10 key, then press the letter of the desired menu item. Most menu items have one letter underlined, indicating their shortcut key. Simple I2C Commands There are two methods for communicating with the MAX5432 EV kit, through the normal user-interface panel (Figure 1) or by using low-level SMBusTM commands available through the 2-Wire Interface utility from the main program's Options | Interface (Advance Users) main menu. A window is displayed (Figure 3) that allows I2C operations, such as SMBusReadByte and SMBusWriteByte. Do not use the SMBusReadByte operation because the MAX5432 does not send data to the master. Note: The I2C dialog boxes accept numeric data in binary, decimal, or hexadecimal. Hexadecimal numbers must be prefixed by $ or 0x. Binary numbers must be exactly eight binary digits. See Figure 3 for an example of this tool. Figure 3 shows a simple SMBus write-byte operation using the included 2-wire interface diagnostics tool. In this example, the software is writing data 0xF8 to the register address 0x11 (write to volatile memory) to the device with the device address 0x50. The data sequence sets the MAX5432 wiper position to 32. Refer to Application Note 476, at www.maxim-ic.com, for information and comparison of the SMBus and I2C protocols. General Troubleshooting Problem: Software reports it cannot find the interface circuit. * Is the interface circuit power LED lit? * * Is the USB cable connected? Has Windows plug-and-play detected the board? Bring up Control Panel -> System -> Device Manager and look at what device nodes are indicated for USB. If there is an "unknown device" node attached to the USB, delete it--this forces plug-and-play to try again. Are jumpers JU1-JU4 properly configured for USB operation? * SMBus is a trademark of Intel Corporation. Figure 3. Simple Low-Level 2-Wire Interface 6 _______________________________________________________________________________________ MAX5432 Evaluation Kit The MAX5432 EV kit is an assembled and tested PCB that evaluates the MAX5432 linear digital potentiometer. The MAX5432 has an end-to-end resistance of 50k and the wiper can be programmed among 32 tap positions. The MAX5432 features an internal nonvolatile memory (EEPROM) used to store the wiper position for initialization during power-up. The on-board I2C-compatible serial interface can communicate at rates up to 400kbps to program the MAX5432. The EV kit uses a MAX5432 IC in an 8-pin TDFN package on a proven 2-layer PCB design. The MAX5432 EV kit provides two options to power the MAX5432 IC. It can operate from the 3.3V supply generated from the USB interface circuit, or from a user-supplied 2.7V to 5.25V external DC power supply. The MAX1840 logic level translators (U7, U8) provide proper I2C-interface operation when using a 2.7V to 5.25V external power supply. EV kit GND pad; connect the power-supply positive terminal to the VIN pad. Table 2 lists the various options for powering the MAX5432 EV kit. I2C Clock and Data Inputs The MAX5432 features clock and data input pins for I2C-compatible communication to control the MAX5432 wiper position. The clock and data input pins are driven by the on-board USB interface circuit or the PCB pads, along with the user-supplied external I2C-compatible controller. An external I2C-compatible controller can be connected to the SCL, SDA, and GND pads to communicate with the MAX5432 IC. Jumpers JU2 and JU3 select the I2C serial-interface signal-control sources for the MAX5432 IC. Table 3 lists the various options for configuring I2C input signal controls. Using an External DC Power Supply The MAX5432 EV kit can be powered by an external 2.7V to 5.25V DC power supply. The EV kit can still be programmed through the USB interface using the software GUI. To connect the EV kit to an external power supply, disconnect the USB cable and install a shunt on pins 2-3 of jumper JU1. Turn off the power supply and connect the power-supply ground terminal to the Address Selection (A0) The MAX5432 EV kit circuit features a jumper that pulls the MAX5432 A0 address pin to VDD or GND to set the slave address. Table 4 shows four possible slave addresses for the MAX5432. The first 4 bits (MSBs) of the slave addresses are always 0101. Bits A2 and A1 are factory programmed (refer to the MAX5432/MAX5433 IC data sheet). Connect the A0 input to either GND or VDD to select the I2C device address for the MAX5432. When using multiple devices, each device must have a unique address to share the I 2 C bus. A maximum of four devices can concurrently share the same bus. Table 2. JU1 Jumper Functions (VDD) Table 3. JU2 and JU3 Jumper Functions (SCL, SDA) Jumper Selection SHUNT VDD PIN POSITION CONNECTED TO 1-2* EV KIT POWERED FROM SHUNT POSITION I2C INTERFACE CONTROL SIGNALS CONNECTED TO I2C INTERFACE SIGNALS CONTROLLED BY 3.3V USB interface circuit 2-3 VIN External power supply (2.7V to 5.25V) Installed* USB interface circuit USB interface circuit and EV kit software Open Not connected Do not use (EV kit will not be powered) Not installed PCB pads User-supplied external I2C interface signals *Default position. *Default position. Table 4. JU4 Jumper Functions (A0) SHUNT POSITION A0 PIN CONNECTED TO ADDRESS BINARY HEX Installed* GND 010100A0Y 0x50 Not installed VDD (through resistor R12) 010100A0Y 0x52 Installed GND 010110A0Y 0x58 Not installed VDD (through resistor R12) 010110A0Y 0x5A PART MAX5432LETA or MAX5433LETA MAX5432META or MAX5433META *Default position. _______________________________________________________________________________________ 7 Evaluates: MAX5432/MAX5433 Detailed Description of Hardware Evaluates: MAX5432/MAX5433 MAX5432 Evaluation Kit Note: The first 7 bits shown are the address. The Y bit in Table 4 is the I2C read/write bit. The I2C protocol states that this bit is a 1 for a read operation or a 0 for a write operation. The Y bit is always set to 0 (write only) because these digital potentiometers do not transmit data to the master device (no readback). Potentiometer or Variable Resistor With or Without Ground Reference The MAX5432 EV kit provides an option to configure the MAX5432 as a potentiometer, a variable resistor, a potentiometer with ground reference, or a variable resistor with ground reference, using jumpers JU5 and JU6. Table 5 lists the various JU5 and JU6 jumper options. Evaluating the MAX5432META, MAX5433LETA, or MAX5433META The MAX5432 EV kit can also evaluate the MAX5432META, MAX5433LETA, or the MAX5433META. Remove the MAX5432LETA IC (U1) and replace it with the desired IC. The MAX5432META, MAX5433LETA, and MAX5433META ICs are pin and functional compatible with the MAX5432LETA IC. Refer to the MAX5432/MAX5433 IC data sheet for a complete description of part-to-part differences. Table 5. JU5 and JU6 Jumper Functions (L Signal and GND) SHUNT POSITION L AND GND PADS H AND W PADS Not installed* Not connected Not connected Potentiometer Installed Not connected Connected Variable resistor Installed Not installed Connected Not connected Potentiometer with ground reference Installed Installed Connected Connected Variable resistor with ground reference JU5 JU6 Not installed* Not installed EV KIT FUNCTION *Default position. 8 _______________________________________________________________________________________ MAX5432 Evaluation Kit Evaluates: MAX5432/MAX5433 Figure 4a. MAX5432 EV Kit Schematic (Sheet 1 of 2) _______________________________________________________________________________________ 9 Evaluates: MAX5432/MAX5433 MAX5432 Evaluation Kit Figure 4b. MAX5432 EV Kit Schematic (Sheet 2 of 2) 10 ______________________________________________________________________________________ MAX5432 Evaluation Kit Evaluates: MAX5432/MAX5433 Figure 5. MAX5432 EV Kit Component Placement Guide--Component Side ______________________________________________________________________________________ 11 Evaluates: MAX5432/MAX5433 MAX5432 Evaluation Kit Figure 6. MAX5432 EV Kit PCB Layout--Component Side 12 ______________________________________________________________________________________ MAX5432 Evaluation Kit Evaluates: MAX5432/MAX5433 Figure 7. MAX5432 EV Kit PCB Layout--Solder Side Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 13 (c) 2008 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc. 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