User's Guide SBAU173 – June 2010 ADS7924EVM and ADS7924EVM-PDK User's Guide ADS7924EVM (Left) and ADS7924EVM-PDK (Right) This user's guide describes the characteristics, operation, and use of the ADS7924EVM, both by itself and as part of the ADS7924EVM-PDK. This evaluation model (EVM) is an evaluation board for the ADS7924, a 12-bit, sampling, low-power, analog-to-digital converter (ADC) with an I2C™ interface. The EVM-PDK allows evaluation of the ADS7924 in some modes of operation, but not all.
www.ti.com 1 2 3 4 5 6 7 8 9 10 Contents EVM Overview ............................................................................................................... 3 Analog Interface ............................................................................................................. 4 Digital Interface .............................................................................................................. 5 Power Supplies ...................................................................
EVM Overview www.ti.com 1 EVM Overview 1.
Analog Interface 1.2 www.ti.com Introduction The ADS7924EVM, shown in Figure 1, is an evaluation module built to the TI Modular EVM System specification. It can be connected to any modular EVM system interface card. The ADS7924EVM is available as a stand-alone printed circuit board (PCB) or as part of the ADS7924EVM-PDK, which includes an MMB3 motherboard and software. As a stand-alone PCB, the ADS7924EVM is useful for prototyping designs and firmware.
Digital Interface www.ti.com 3 Digital Interface 3.1 Serial Data Interface The ADS7924EVM is designed to easily interface with multiple control platforms. Samtec part numbers SSW-110-22-F-D-VS-K and TSM-110-01-T-DV-P provide a convenient 10-pin, dual-row, header/socket combination at J3. This header/socket provides access to the digital control and serial data pins of the ADC. Consult Samtec at http://www.samtec.com or call 1-800-SAMTEC-9 for a variety of mating connector options.
Power Supplies 4 www.ti.com Power Supplies J2 is the power-supply input connector. Table 3 lists the configuration details for J2. Table 3. J2 Configuration: Power-Supply Input Pin No. Pin Name Function Required J2.1 +VA Unused No J2.2 –VA Unused No J2.3 +5VA +5V analog supply Always J2.4 –5VA –5V analog supply No J2.5 DGND Digital ground input Yes J2.6 AGND Analog ground input Yes J2.7 +1.8VD 1.8V digital supply Sometimes J2.8 VD1 Unused No J2.9 +3.3VD 3.
External Buffer www.ti.com 5 External Buffer The ADS7924 device has the option of selecting an external buffer going from MUXOUT to ADCIN. An OPA363 can be used as a buffer and is selected through the configuration of J11. Connecting pins 1 and 2 together will bypass the external buffer, while connecting pins 1 and 3 and pins 2 and 4 will complete the circuit for the buffer. Figure 2 shows jumper J11 as it appears on the EVM in its default position, using the buffer. Figure 2.
EVM Operation 6.3 www.ti.com Default Jumper Settings and Switch Positions Figure 3 shows the jumpers found on the EVM and the respective factory default conditions for each. Figure 3. ADS7924EVM Default Jumper Locations Table 5 lists the jumpers found on the EVM and the factory default conditions for each of the configurable jumpers. Table 5. List of Configured Jumpers Jumper Default Position Switch Description J5.1-J5.2 Connected I2C address selector J6.1-J5.
ADS7924EVM-PDK Kit Operation www.ti.com 7 ADS7924EVM-PDK Kit Operation This section provides information on using the ADS7924EVM-PDK, including setup, program installation, and program usage. To prepare Step 1. Step 2. Step 3. Step 4. Step 5. Step 6. to evaluate the ADS7924 with the ADS7924EVM-PDK, complete the following steps: Install the ADCPro software (if not already installed) on a PC. Install the ADS7924EVM-PDK EVM plug-in software. Complete the USB driver installation process.
ADS7924EVM-PDK Kit Operation www.ti.com If the Virtual COM Port driver has already been installed, press the Yes option. If not, press No; the software will continue with the TUSB3410 installation. The screen shown in Figure 5 appears. The Cancel button will stop the installation process. Figure 5. Virtual COM Port Driver Installation Once the InstallShield wizard is complete, the software will first prompt an uninstall process that will remove any previous versions of the software.
ADS7924EVM-PDK Kit Operation www.ti.com 7.2 EVM Power Supply The ADS7924EVM-PDK is powered completely from the USB connection on the MMB3. The MMB3 provides 3.3V and ±5V to the ADS7924EVM. 7.3 Running the Software and Download of Firmware to MMB3 NOTE: The software is continually under development. These instructions and screen images are current at the time of this writing, but may not exactly match future releases. The program for evaluating the ADS7924EVM-PDK is called ADCPro.
ADS7924EVM-PDK Kit Operation www.ti.com 2. Select ADS7924EVM from the EVM drop-down menu. The ADS7924EVM-PDK plug-in appears in the left pane, as shown in Figure 8. Figure 8. ADS7924EVM-PDK Plug-In Display Window The ADS7924EVM-PDK plug-in window has a status area at the top of the screen. When the plug-in is first loaded, the plug-in searches for the board. You will see a series of messages in the status area indicating this action.
ADS7924EVM-PDK Kit Operation www.ti.com 3. If the plug-in cannot connect to the EVM, you will see a window as shown in Figure 9. This message indicates that the autoscan process for an available COM port has failed, giving you several different options. Figure 9. EVM COM Port Autoscan Prompt Window 4. If the Rescan option is unsuccessful, you can manually set the COM port to connect to the EVM. The Manual COM Port selection window is shown in Figure 10. Figure 10. Manual COM Port Selection Window 5.
ADS7924EVM-PDK Kit Operation www.ti.com 6. Switch the BSL switch (SW4) on the MMB3 to the BSL position (to the left) as instructed, then press OK. The plug-in will download the firmware to the MMB3. This operation may take a couple of minutes, so the progress is updated in the message at the top of the ADS7924 plug-in window (as Figure 12 shows). The firmware is saved in flash memory on the MMB3, so this operation should need to only be performed once. Figure 12.
Evaluating Performance with the ADCPro Software www.ti.com 7. When the firmware download completes, the message box shown in Figure 13 appears. Follow the on-screen instructions and the plug-in should now connect to the EVM. Figure 13. MMB3 Firmware Download Complete 8 Evaluating Performance with the ADCPro Software The evaluation software is based on ADCPro, a program that operates using a variety of plug-ins. (The ADS7924EVM plug-in is installed as described in the installation section, Section 7.
Evaluating Performance with the ADCPro Software 8.1.1 www.ti.com ADC Configuration Tab The first tab of the ADS7924EVM plug-in is the ADC tab. This tab controls the I2C selection, ADC operation, sleep functions, and the PWRCON control for the external buffer. There are four sections within this tab. The ADC tab is shown in Figure 15. Figure 15. ADC Tab The first section controls the I2C address.
www.ti.com 8.1.2 Evaluating Performance with the ADCPro Software Interrupts Tab The second tab of the ADS7924EVM plug-in is the Interrupts tab. This tab corresponds primarily to the Interrupt CONFIG Register of the ADS7924. A set of pushbuttons are used to control the bit selections within this register. The Interrupts tab is shown in Figure 16. Figure 16. Interrupts Tab The BUSY/INT Select allows the user to generate an interrupt or a BUSY signal.
Evaluating Performance with the ADCPro Software 8.1.3 www.ti.com Alarms Tab The Alarms tab of the ADS7924EVM plug-in is shown in Figure 17. The ADS7924 offers an independent alarm control that can be enabled for each channel. An 8-bit upper limit and lower limit can be set independently. An alarm indicator shows the alarm status.
www.ti.com 8.1.4 Evaluating Performance with the ADCPro Software About Tab The About tab displays information about the EVM and software, as shown in Figure 18. The Plugin Version and Firmware Version indicators show the version numbers of the plug-in and firmware code, respectively. The Notes indicator may show relevant notes about the released plug-in or firmware code, if any are available. Figure 18.
Evaluating Performance with the ADCPro Software 8.2 www.ti.com Collecting Data Once you have configured the ADS7924 for your test scenario, press the ADCPro Acquire button to start the collection of the number of datapoints specified in the Test plug-in Block Size control. The ADS7924EVM-PDK plug-in disables all the front panel controls while acquiring data, and displays a progress bar as Figure 19 shows. Figure 19. Progress Bar While Acquiring Data 8.
Schematics and Layout www.ti.com 9 Schematics and Layout Schematics for the ADS7924EVM are appended to this user's guide. The bill of materials is provided in Table 7. 9.1 Bill of Materials Table 7. Bill of Materials Item No. Qty Value Ref Des 1 1 2.2mF C4 Description Manufacturer 2 8 0.
Appendix: Setting Up the ADS7924EVM-PDK 10 www.ti.com Appendix: Setting Up the ADS7924EVM-PDK The ADS7924EVM-PDK contains both the ADS7924EVM and the MMB3 motherboard; the devices are shipped connected. However, if you only order the ADS7924EVM and already have the MMB3, you must make sure the MMB3 is set back to its default conditions in order to load the firmware onto the motherboard. Follow these steps to set up the ADS7924EVM-PDK Step 1. Unpack the ADS7924EVM kit. Step 2.
Appendix: Setting Up the ADS7924EVM-PDK www.ti.com 3. Plug the ADS7924EVM into the MMB3 as Figure 21 illustrates. Figure 21. Connecting ADS7924EVM to MMB3 CAUTION Do not misalign the pins when plugging the ADS7924EVM into the MMB3. Check the pin alignment carefully before applying power to the PDK. Step 3. Set the jumpers and switches on the ADS7924EVM as shown in Figure 3 (note that these settings are the factory-configured settings for the EVM).
Appendix: Setting Up the ADS7924EVM-PDK www.ti.com 10.1 About the MMB3 The MMB3 is a Modular EVM System motherboard. It is designed around the MSP430F449, a low-power microcontroller from Texas Instruments. Figure 22 shows a block diagram of the MMB3. Figure 23 illustrates the MMB3. USB USB RESET +5VA -5VA +5VD PWR & VREF +3.3V +1.8V +10V TUSB3410 -10V Supplied to Daughtercard Power Connector LCD DISPLAY 2.
Appendix: Setting Up the ADS7924EVM-PDK www.ti.com Figure 23. MMB3 The MMB3 was designed to be used as a stand-alone demonstration platform for low-speed data converters. It features an onboard, 20-bit digital-to-analog converter (DAC) that can be used as a signal source for an ADC under test, and has a joystick for user control of functions on the board when it is not controlled by a PC. These features are experimental and not supported in the ADS7924EVM-PDK at this time.
1 2 4 REVISION HISTORY 3 REV TP3 AGND 1 TP7 DGND J6 TP4 VDD BVDD TP6 +3.3VD C1 C2 10uF 10uF JPR-2X1 D BVDD +3.3VD BVDD PWRCON R3 10k ADCIN 6 2 CH2 12 A0 DGND CH0 RESET DAUGHTER-ANALOG VDD +5V +3.3VD +1.8VD OPA363IDBV U2 EN BVDD C10 C11+3.3VD 0.1uF 0.1uF U5 1 3 2 VDD 6 4 5 VCCA VCCB A B GND DIR BVDD +3.3VD C6 C8 C9 +3.3VD 0.1uF 0.1uF J10 R1 100 1 2 3 4 C4 2.
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