Datasheet
Table Of Contents
- XTR108EVM-USB Evaluation Board and Software Tutorial
- 1 Overview
- 2 Hardware Overview
- 3 Hardware Setup
- 3.1 Electrostatic Discharge Warning
- 3.2 Connecting the Hardware
- 3.3 Connecting Power and USB to the USB DAQ Platform
- 3.4 Connecting Loop Power Supply to the XTR108EVM-USB Interface Board
- 3.5 Connecting Outputs to a Digital Multimeter (DMM)
- 3.6 USB DAQ Platform Default Jumper Settings
- 3.7 XTR108EVM-USB Interface Board Default Jumper Settings
- 3.8 XTR108EVM-USB Sensor Board Default Jumper Settings
- 4 Software Setup
- 5 Software Overview
- 6 General Operating Tips
- 7 Hardware Documentation
- 8 Appendix
- Important Notices
Appendix
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The USB-DAQ Platform SPI protocol supports four clock and data line modes of operation. These modes
are summarized in Table 32. The first mode, BREH, is used by the XTR108EVM-USB.
Table 32. SPI Modes of Operation
Mode Clock Polarity Description (CPOL) Clock Transition for Data Polarity Description (CPHA)
Data are read by the USB-DAQ on the clock rising edge. Data are
Clock idles low
BREH changed by the USB-DAQ on the clock falling edge. Data are sampled on
CPOL = 0
the first clock edge. CPHA = 0.
Data are read by the USB-DAQ on the clock falling edge. Data are
Clock idles low
BREL changed by the USB-DAQ on the clock rising edge. Data are sampled on
CPOL = 0
the second clock edge. CPHA = 1.
Data are read by the USB-DAQ on the clock falling edge. Data are
Clock idles high
AFEH changed by the USB-DAQ on the clock rising edge. Data are sampled on
CPOL = 1
the first clock edge. CPHA = 0.
Data are read by the USB-DAQ on the clock rising edge. Data are
Clock idles high
AFEL changed by the USB-DAQ on the clock falling edge. Data are sampled on
CPOL = 1
the second clock edge. CPHA = 1.
The USB-DAQ also supports a set of generic commands used to enable or disable power supplies, read
from internal ADCs, set the output of internal DACs, and set the voltage of control pins. The XTR108EVM-
USB uses the GPIO pin functionality to control the relay driver U1 on the Interface Board. These
commands are given in Table 33.
Table 33. General USB-DAQ Commands
Command Description
CMD Always the first mnemonic in a general USB-DAQ command.
Sets the eight control pins according to the value written.
Each control pin is assigned a location in the 8-bit control word, where CTRL8 is the
Example: CTRL 0, CTRL 3, CTRL 128,
MSB and CTRL1 is the LSB. For example, write CTRL 0 to turn off all control pins. To
CTRL 255
turn on the CTRL1 and CTRL2 pins, write CTRL 3. To turn on only the CTRL8 pin,
write CTRL 128.
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XTR108EVM-USB Evaluation Board and Software Tutorial SBOU123–March 2012
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