Related Manuals for Texas Instruments ADS1254
Summary of Contents for Texas Instruments ADS1254
- Page 1 ADS1254 Analog to Digital Converter Evaluation Module User’s Guide Data Acquisition Products May 2002 SLAU083...
- Page 2 IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete.
- Page 3 EVM IMPORTANT NOTICE Texas Instruments (TI) provides the enclosed product(s) under the following conditions: This evaluation kit being sold by TI is intended for use for ENGINEERING DEVELOPMENT OR EVALUATION PURPOSES ONLY and is not considered by TI to be fit for commercial use. As such, the goods being provided may not be complete in terms of required design-, marketing-, and/or manufacturing-related protective considerations, including product safety measures typically found in the end product incorporating the goods.
- Page 4 EVM schematic located in the EVM User’s Guide. When placing measurement probes near these devices during operation, please be aware that these devices may be very warm to the touch. Mailing Address: Texas Instruments Post Office Box 655303 Dallas, Texas 75265 Copyright 2002, Texas Instruments Incorporated...
- Page 5 This manual helps you quickly set up the evaluation module and its accompanying software, so that you can rapidly test and evaluate the ADS1254. Complete circuit descriptions, as well as schematic diagrams, PCB layouts, and bill of materials, are also included.
- Page 6 Windows is a trademark of Microsoft Corporation. If You Need Assistance. . . If you have questions about this or other Texas Instruments data converter evaluation modules, feel free to e−mail the data converter application team at [email protected]. Include the product name in the subject heading.
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Page 7: Table Of Contents
..............The ADS1254 . - Page 8 Contents Physical Description ............. Board Layouts .
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Page 9: Introduction
Page The ADS1254 .......... -
Page 10: The Ads1254
PC over the RS-232 connection. Because of this, data read from the ADS1254 is stored in an onboard RAM, where it is kept until retrieved by the host system. This process is controlled by the user through the ADS1254EVM... -
Page 11: Analog Inputs
DIGITAL VDD SOURCE 1.3 Analog Inputs Analog input is supplied through the eight-way screw terminal block, J2. Each input is connected to the ADS1254 through a 1-kΩ resistor. The inputs are not protected against overvoltage. 1.4 Prototyping Area A prototyping area is provided on the ADS1254EVM. This may be used to incorporate additional circuitry, such as special reference or conditioning circuits, into the system. -
Page 12: Host Computer Requirements
Host Computer Requirements 1.6 Host Computer Requirements The ADS1254EVM software is designed to run on a PC running any Windows platform (Windows 95, 98, NT, 2000, etc.). Minimum Requirements: IBM-compatible 486 PC or higher Windows 95/98/2000 or NT4.0 64 MB RAM minimum 20 MB available hard disk space CD-ROM drive Available serial port... -
Page 13: Getting Started
Chapter 2 Getting Started This chapter guides you through unpacking your EVM and setting it up so you can begin working with it immediately. Topic Page Unpacking the EVM ......... . . Default Configuration . -
Page 14: Unpacking The Evm
ADS1254EVM board 9-pin D-sub male-female serial cable Software CD-ROM If any of these items are missing, contact Texas Instruments to receive replacements. 2.2 Default Configuration Although much of the ADS1254EVMs operation is controlled by the host PC, some configuration must be done directly on the board, using five jumpers (shorting blocks). -
Page 15: Quick Start
Quick Start 2.3 Quick Start Once the ADS1254EVM has been unpacked from its shipping container, and you have verified that the board is configured as shown in Table 2−1, it can be powered on and tested. First, connect the board to the host PC using the supplied 9-pin serial cable. Then power the board on by plugging a wall power adapter into a suitable ac power source and plugging the barrel plug into the barrel jack on the ADS1254EVM, or by connecting your laboratory power supply to the external... - Page 16 Quick Start The setup window appears first, allowing you to make adjustments to the programs configuration. For the test run, you should select the serial port to which the ADS1254EVM is connected, using the serial port menu. If no serial ports are available, a message box appears informing you that the program cannot run.
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Page 17: Operation
− Chapter 3 Operation This chapter describes each function of the ADS1254EVM, and how to use the accompanying software to control the ADS1254. Topic Page Jumpers ........... . . -
Page 18: Jumpers
2 −3. 3.1.3 JMP4: Reference Disconnect JMP4 is used to connect an external reference directly to the ADS1254, with- out using the onboard filtering. Removing this jumper disconnects the ADS1254 reference pin. External reference voltage must be applied to pin 2. -
Page 19: Jmp5: Mcu Disable
DSK, since the clock generator is only supplied from the onboard regulators. If you want to use an external system to control the ADS1254, instead of the onboard MCU, you must connect this jumper to prevent conflicts with the MCU. -
Page 20: Reset Switch
Reset Switch 3.2 Reset Switch Switch SW1 is a miniature pushbutton which, when pressed, forces the MCUs RESET line low. When released, the MCU enters a reset cycle. If communication becomes disrupted between the host and the board, or the board is unresponsive, pressing RESET returns the system to normal operation. -
Page 21: J6: 3.3-V Jtag Port
Connectors 3.3.2 J6: 3.3-V JTAG Port This connector is used mainly during firmware development. It provides a fast way to download firmware into the MCU, and also allows access to the MCU’s hardware debugging features. If you have MSP430 software development tools, you can use this port to write your own firmware for the ADS1254EVM. -
Page 22: J1, J4, J5, Bt1: Power Connectors
Connectors 3.3.3 J1, J4, J5, BT1: Power Connectors The ADS1254EVM features a flexible power supply. Externally generated power, the onboard regulator circuitry and an ac adaptor, or a 9-V battery may all be used to supply power. Furthermore, the separated analog and digital power supplies may be powered differently;... -
Page 23: J3: External Reference Input
R2, C3, and U4, and bypassed by C10. It is also possible to supply a reference voltage directly to the ADS1254 by dis- connecting JMP4 and connecting the reference to pin 2. Table 3−9. J3: External Reference Input... -
Page 24: J8: 3.3-V Jtag Port
GPIO and peripheral signals from the DSP. The ADS1254, being a purely SPI part, does not make use of the DSP external parallel bus; therefore, only one signal connection from J9, a timer output, is used. -
Page 25: Tp1−6: Test Points
The test points are used to monitor certain signals on the board, or to connect external signals to the ADS1254. Consult the ADS1254 data sheet for information on the signals connected directly to the ADS1254. Table 3−11. TP1−6: Test Points... -
Page 26: Circuit Description
3.4.3 Clock Generation The ADS1254 requires a system clock, from which it derives its sampling rate; the sampling rate is the system clock frequency divided by 384. The system clock’s maximum specified rate is 8 MHz (maximum sampling frequency is 20833 Hz);... -
Page 27: Firmware And Host Communication
Firmware and Host Communication The ADS1254EVM firmware controls the acquisition of data from the ADS1254 and the clock generation circuitry. It is capable of receiving data from the ADS1254 at the full data rate, while simultaneously performing averaging. Communication with the host is performed using TI’s CSR-232 protocol, which is designed for efficient system control over point-to-point serial links. -
Page 28: Host Pc Software
Host PC Software 3.5 Host PC Software After having installed the software for the ADS1254EVM as described in Section 2.3, you can use it to evaluate the ADS1254. The software is described in the following subsections. 3.5.1 Main Window The main window is shown in Figure 3−1. The window is shown as it first comes up when the program is started. - Page 29 Host PC Software 3) The ADS1254EVM begins collecting samples. The ADS1254EVM informs the software of the progress of the acquisition approximately four times a second; this information is displayed in the status bar at the bottom of the window. 4) The ADS1254EVM tells the software that the acquisition has completed. 5) The software begins reading sample data from the ADS1254EVM.
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Page 30: Display Modes
Host PC Software 3.5.2 Display Modes The evaluation software offers four ways to display sample data: Scope displays the data as a sample number versus amplitude graph, similar to an oscilloscope FFT displays a fast Fourier transform of the data on a frequency versus magnitude graph Histogram displays the data on a value versus count graph (histogram) Data list displays the raw sample data in a list... -
Page 31: Setup Dialog
As integers: Each sample is displayed as a signed base-10 integer. The sample values are shown exactly as received from the ADS1254. As hexadecimal integers: Each sample is displayed as an unsigned hexadecimal number. -
Page 32: Setup Dialog
Host PC Software Figure 3−2. Setup Dialog 3.5.3.1 Serial Port Menu The serial port menu allows you to choose which serial port to use for communication with the ADS1254EVM. The ADS1254EVM must be connected to the port selected here, or the program will not work. All of the available ports are shown in the menu. - Page 33 The allowable values are all shown in the Averaging menu; up to 32,768 samples per reading can be averaged together. Selecting none from the menu—the default—means that no averages are taken, and data is returned as read from the ADS1254. 3.5.3.5 Serial Monitor Checking this box causes the serial monitor window to appear when the setup dialog is closed.
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Page 35: Physical Description
Chapter 4 Physical Description This chapter contains the schematic drawings and PCB layouts for the ADS1254EVM board. Topic Page Board Layouts ..........Schematics . -
Page 36: Board Layout Top Layer
Board Layouts 4.1 Board Layouts Figure 4−1. Board Layout Top Layer... -
Page 37: Board Layout Bottom Layer
Board Layouts Figure 4−2. Board Layout Bottom Layer Physical Description... - Page 38 Schematics 4.2 Schematics The ADS1254 schematics are shown on the following pages.