Evaluation Board User Guide UG-062 One Technology Way * P.O. Box 9106 * Norwood, MA 02062-9106, U.S.A. * Tel: 781.329.4700 * Fax: 781.461.3113 * www.analog.com Evaluation Board for AD7843/AD7873 Resistive Touch Screen Controllers FEATURES GENERAL DESCRIPTION Easy access to the AD7843/AD7873 Connects to any PC USB port Self-contained evaluation system Test points for easy access to signals Touch screen included The AD7843/AD7873 evaluation board allows the user to evaluate all features of the AD7843/AD7873. The evaluation software allows the user to change the settings on the AD7843/ AD7873. The users can connect the touch screen to the J3 connector, or use the on-board variable resistors, to evaluate the touch screen function. PACKAGE CONTENTS The AD7843/AD7873 evaluation board kit contains the following: * The AD7843/AD7873 evaluation board * A USB cable * A CD with the evaluation software, schematics, and this user guide * A 4-wire resistive screen EVALUATION BOARD BLOCK DIAGRAM VOLTAGE REGULATOR 0.1F J7-2 1.0F TO 10F (OPTIONAL) MAIN BATTERY 3.3V TEST POINT CS X+ +VCC CS Y+ PENIRQ GND Y- DIN X- BUSY INT1 TEST POINTS INT2 3.3V +VCC MISO DOUT SCLK MOSI SPI INTERFACE IN4/AUX AD7843/ AD7873 3.3V DCLK VREF J2 IN3/VBAT HOST TEST POINTS OPTIONAL R-C X- J1-1 X+ Y+ J1-2 J3-1 J1-3 J3-2 Y- J1-4 J3-3 J3-4 08633-001 TOUCH SCREEN NOTES 1. THE AUX AND VBAT PINS ONLY APPLY TO THE AD7873. THE IN3 AND IN4 PINS ONLY APPLY TO THE AD7843. Figure 1. See the last page for an important warning and disclaimers. Rev. 0 | Page 1 of 12 UG-062 Evaluation Board User Guide TABLE OF CONTENTS Features .............................................................................................. 1 Indicator LED Descriptions .........................................................4 Package Contents .............................................................................. 1 Evaluation Board Software ...............................................................5 General Description ......................................................................... 1 Installing the Software ..................................................................5 Evaluation Board Block Diagram ................................................... 1 Running the Software ...................................................................5 Revision History ............................................................................... 2 Evaluation Demonstration ...............................................................6 Evaluation Board .............................................................................. 3 Single Conversion Block...............................................................6 Setting Up the Evaluation Board ................................................ 3 Continuous X-Y Conversion .......................................................7 Evaluation Board Description .................................................... 3 Touchscreen ...................................................................................8 Evaluation Board Hardware ............................................................ 4 Schematics ..........................................................................................9 Connector Function Descriptions ............................................. 4 ESD Caution................................................................................ 12 Link Function Descriptions ........................................................ 4 REVISION HISTORY 12/09--Revision 0: Initial Version Rev. 0 | Page 2 of 12 Evaluation Board User Guide UG-062 EVALUATION BOARD The evaluation board contains the following main components, which are also shown in the functional block diagram (see Figure 1): SETTING UP THE EVALUATION BOARD Follow these steps to set up the AD7843/AD7873 evaluation board: * * * * * * * * * * * Install the evaluation software (CD) before connecting the board. Plug the USB connector from the USB port on your PC into the mini-USB socket on the evaluation board. The power indicator LED on the board should turn on. Ensure that all switches and links are in their default positions. Start the AD7843/AD7873 evaluation software. * EVALUATION BOARD DESCRIPTION The AD7843/AD7873 evaluation board allows the user to evaluate all features of the AD7843 and AD7873. The board is powered via the USB connection to the host PC. The evaluation software allows data to be read from and written to the AD7843/AD7873. Install the evaluation software on the PC before plugging in the board. AD7843/AD7873 IC USB microcontroller IC, CY7C68013-CSP LED indicators for power and PENIRQ EEPROM for USB initialization information Connector for USB interface Connector for touch screen Screw-top connectors for the following signals: X-, Y+, X+, Y-, +VCC, VREF, and GND Test points for the following signals: DOUT, DIN, DCLK, CS, PENIRQ, BUSY, +VCC, and VBAT. The printed circuit board (PCB) schematics are shown in Figure 6 and Figure 7. Rev. 0 | Page 3 of 12 UG-062 Evaluation Board User Guide EVALUATION BOARD HARDWARE CONNECTOR FUNCTION DESCRIPTIONS Table 1. Name J6 J13-1 Mnemonic USB interface Power J13-2 J7-2 AGND EXT_VREF J2 J5 AUX EXT_BAT J3 Touch screen J1 Touch screen Description Plug the USB cable directly from the PC into this connector. It is a type USB Mini-B socket. Power can be supplied to the board by either the USB cable or the power connector, J13. If L5 is in Position B, power is supplied via the USB cable. If L5 is in Position A, power is supplied from the J13-1 connector. An external ground can be connected via the J13-2 connector. Connector J7-2 can be used to apply a signal to the VREF input on the AD7843/AD7873. L6 must be in Position A for this connector to be linked to the AD7843/AD7873. If L6 is in Position B, 3.3 V is applied to the VREF input. The J2 connector can be used to apply a signal to the AUX input on the AD7843/AD7873. Connector J5 can be used to apply a signal to the VBAT input on the AD7843/AD7873. L7 must be in Position B for this connector to be linked to the AD7843/AD7873. The touch screen included with the demonstration kit can be connected directly into the AD7843/AD7873 demonstration board using this connector. Connect as follows: X- to J3-1, Y+ to J3-2, X+ to J3-3, and Y- to J3-4. This connector can be used to connect a touch screen to the AD7843/AD7873. Connect as follows: X- to J1-1, Y+ to J1-2, X+ to J1-3, and Y- to J1-4. LINK FUNCTION DESCRIPTIONS Table 2. Name L1 Mnemonic X+ Default Position A L2 Y+ A L3 X- A L4 Y- A L5 Input power B L6 REF input A L7 BAT input A Description This jumper selects the X+ input on the AD7843/AD7873. If the jumper is in Position A, the X+ input comes from the J1-3 or J3-3 touch screen connectors. This jumper selects the Y+ input on the AD7843/AD7873. If the jumper is in Position A, the Y+ input comes from the J1-2 or J3-2 touch screen connectors. This jumper selects the X- input on the AD7843/AD7873. If the jumper is in Position A, the X- input comes from the J1-1 or J3-1 touch screen connectors. This jumper selects the Y- input on the AD7843/AD7873. If the jumper is in Position A, the Y- input comes from the J1-4 or J3-4 touch screen connectors. This jumper selects the input power for the evaluation board. If the jumper is in Position A, power for the board must be supplied through the J13-1connector. If the link is in Position B, the USB connection supplies the power for the board. This jumper selects the input signal to the reference input on the AD7843/AD7873. If the jumper is in Position A, REF is connected to Pin 2 of the J7 (J7-2) connector. An input voltage can then be connected to J7-1. If the link is in Position B, REF is connected to 3.3 V. This jumper selects the input signal to the VBAT input on the AD7843/AD7873. If the jumper is in Position B, VBAT is connected to the J5 connector. An input voltage can then be connected to J5. If the link is in Position A, VBAT is connected to a variable resistor, R9. The user can vary R9 to change the input voltage on the VBAT pin. The maximum resistance of R9 is 10 k. INDICATOR LED DESCRIPTIONS Table 3. Name D1 Mnemonic PENIRQ Description This LED indicates when lit (green) that the PENIRQ interrupt is active on the AD7843/AD7873. Rev. 0 | Page 4 of 12 Evaluation Board User Guide UG-062 EVALUATION BOARD SOFTWARE The AD7843/AD7873 evaluation software configures the part in master mode; therefore, unless the screen is touched, no measurements are taken. The user can change the register settings, plot, and save data from the AD7843/AD7873 and plot the X and Y positions using the evaluation software. INSTALLING THE SOFTWARE Before running the software, ensure that the evaluation board is plugged into the USB port of the host PC. Run the software from the AD7843/73 Evaluation Software directory. When the software starts, the AD7873 Communication Demo dialog box appears, as shown in Figure 2. If the software downloads properly, a Download Ok message appears in the lower left corner of the AD7873 Communication Demo dialog box. If this message does not appear, the software has not initialized properly. If this happens, exit the software and restart it. If an error persists, exit the software, disconnect the USB connector from the board, reconnect the USB connector to the board, and reinstall the evaluation software. 08633-002 Install the software before the evaluation board is plugged into the host PC. The evaluation software is installed by running the AD7843/73EvaluationSoftwareInstall.exe program, found on the CD within the evaluation board kit. The user must agree to Analog Devices, Inc., licensing agreement before the software can be installed. The software installs and saves into the AD7843/73 Evaluation Software directory. RUNNING THE SOFTWARE Figure 2. AD7843/AD7873 Evaluation Software Start-Up Dialog Box Rev. 0 | Page 5 of 12 UG-062 Evaluation Board User Guide EVALUATION DEMONSTRATION The evaluation demonstration allows the user to set up the AD7843/AD7873 control register according to requirements. The demonstration also displays the X and Y coordinates SINGLE CONVERSION BLOCK The Single Conversion Block tab allows user to read and modify the values of the Control Register bits. By using the software, the user can program the main features of the AD7843/ AD7873. When any of the programmable features change, the control register bit display section is updated automatically. The user can read specific conversion results by supplying the channel address in the control register bits (A2, A1, A0). To read more than one channel, insert the number of channels you want read into the Number of Channels box. Click Get Data to see the results of the ADC conversion on the right side of the screen. The user can modify the SPI Clock frequency: setting from 10 kHz to 600 kHz by using the slider shown in Figure 3. Control Register 08633-003 Users can write to the control register by clicking on the corresponding bit boxes. The programmable features in the control register are the following: the power management bits (PD1, PD0 (LSB)), the single or differential mode (SER/DFR), the ADC mode (8 bits or 12 bits, Mode), the ADC Channel Start Address (A2, A1, A0), and the Initiate start (MSB) bit. ALLOWS YOU TO MODIFY THE SPI CLOCK FREQUENCY Figure 3. Single Conversion Block Rev. 0 | Page 6 of 12 Evaluation Board User Guide UG-062 CONTINUOUS X-Y CONVERSION Connecting a Touch Screen to the Board When the user clicks the Continuous X-Y Conversion tab, the screen shown in Figure 4 appears. ADC values measured by the AD7843/AD7873 can be graphed on this screen. This screen also allows the user to program PD0 (LSB), PD1, SER/DFR, and the mode bits contained in the control register (Address 0x90). Follow these steps to connect the touch screen included in the evaluation board kit to the board: * * * The evaluation board offers the following three options to measure the X and Y coordinates: * * Connect the screen provided in the evaluation kit to Connector J3. Connect any other screen to Connector J1. Use the variable resistors, R7 and R6, to simulate the resistance of the screen. * Using the Variable Resistors If no touch screens are available, the variable resistors, R7 and R6, can be used to mimic a touch screen. Ensure that L1, L2, L4, and L6 are in Position B. The variable resistors can then be adjusted to mimic a user touching a screen. X, Y COORDINATES MEASUREMENTS 08633-004 * Use Connector J3. Ensure that L1, L2, L3, and L4 are in Position A. Connect the 4-wire resistive screen with the green side of the flex tail facing the board. When it is secure in the connector, flip the tail over so that the board lies flat with the green side of the flex tail facing upward. The included touch screen requires a strong activation force. When using the screen, ensure that you press hard on it. Use Connector J1 to connect any other touch screens to the board. Figure 4. Result Plotting Screen Rev. 0 | Page 7 of 12 UG-062 Evaluation Board User Guide TOUCHSCREEN Click Continuous X-Y Conversion to display the Touchscreen window, see Figure 5. The X and Y coordinates from the screen are displayed in Figure 5. The window approximates a real touch screen application. If a touch screen is connected to the AD7843/AD7873 evaluation board, then any touch on the screen is plotted in this window. 08633-005 The Clear button deletes everything written on the screen. Figure 5. Touchscreen Window Rev. 0 | Page 8 of 12 Evaluation Board User Guide UG-062 SCHEMATICS 08633-006 Figure 6. Evaluation Board Schematic AD7843/AD7873 Section Rev. 0 | Page 9 of 12 UG-062 Evaluation Board User Guide 08633-007 Figure 7. AD7843/AD7873 Evaluation Board Schematic USB Section Rev. 0 | Page 10 of 12 UG-062 08633-008 Evaluation Board User Guide Figure 8. AD7843AD7873 Evaluation Board Component Side Rev. 0 | Page 11 of 12 UG-062 Evaluation Board User Guide NOTES ESD CAUTION Evaluation boards are only intended for device evaluation and not for production purposes. Evaluation boards are supplied "as is" and without warranties of any kind, express, implied, or statutory including, but not limited to, any implied warranty of merchantability or fitness for a particular purpose. No license is granted by implication or otherwise under any patents or other intellectual property by application or use of evaluation boards. Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Analog Devices reserves the right to change devices or specifications at any time without notice. Trademarks and registered trademarks are the property of their respective owners. Evaluation boards are not authorized to be used in life support devices or systems. (c)2009 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. UG08633-0-12/09(0) Rev. 0 | Page 12 of 12