Datasheet
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Digital Interface
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.
All logic levels on J3 are 3.3V CMOS, except for the I
2
C pins. These pins conform to 3.3V I
2
C™ rules.
Table 2 describes the J3 serial interface pins.
Table 2. J3: Serial Interface Pins
Pin No. Pin Name Signal Name I/O Type Pull-Up Function
J3.1 CNTL RST_H In None ADS7924 reset
J3.2 GPIO0 Unused — None
J3.3 CLKX Unused — None
J3.4 DGND DGND In/Out None Digital ground
J3.5 CLKR Unused — None
J3.6 GPIO1 Unused — None
J3.7 FSX Unused — None
J3.8 GPIO2 Unused — None
J3.9 FSR Unused — None
J3.10 DGND DGND In/Out None Digital ground
J3.11 DX Unused — None
J3.12 GPIO3 Unused — None
J3.13 DR Unused — None
J3.14 GPIO4 Unused — None
J3.15 INT INT_H Out None ADS7924 interrupt
J3.16 SCL SCL_H I
2
C High I
2
C clock
J3.17 TOUT Unused — None
J3.18 DGND DGND In/Out None Digital ground
J3.19 GPIO5 Unused — None
J3.20 SDA SDA I
2
C High I
2
C data
Some pins on J3 have weak pull-up resistors. These resistors provide default settings for many of the
control pins. Many pins on J3 correspond to ADS7924 pins and are connected to them through either
voltage-level translators or the I
2
C bus level translator. See the ADS7924 product data sheet for complete
details on these pins.
3.2 Data Output
All output data communications are directed through the I
2
C communication protocol. The data from all
channels can be observed through monitoring SDA_H and SCL_H. These signals are used by the
ADS7924EVM-PDK to read back and display all the channel data via the ADCPro Software.
5
SBAU173–June 2010 ADS7924EVM and ADS7924EVM-PDK User's Guide
Copyright © 2010, Texas Instruments Incorporated