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ADS112C04: i cant receive ack!

user5395380
Prodigy 60 points
Part Number: ADS112C04

    i can't receive the ack when i send command to ads112c04. could anyone tell me how to check the chip.

  • 0
    TI__Guru** 113765 points

    Hi user5395380,

    The best method of checking the ADS112C04 is to verify that both the AVDD and DVDD supplies are at the nominal operating voltage, the RESET pin is logic high, the device address pins are set to a valid voltage, and the SDA and SCL lines are pulled high.

    Once this is checked, you need to verify the communication is as you would expect with an oscilloscope or logic analyzer.  9 times out of 10 the issue I've seen  regarding a NACK is incorrect addressing.  Make sure that the address sent is left-shifted by 1 in the code before transmitting.  For example, if the device address is set to 0x40 (A1 and A0 pins at DGND) and you want to write to the device the byte transmitted would be 0x80 and if you want to read from the device the byte transmitted is 0x81 where the first 7 bits are the address and the last bit is the R/nW bit.  If you are correctly addressing the device you should see an ACK.  

    Writing a command to the device consists of addressing the ADS112C04 as a write (0x80) followed by the command.  For example, to issue the START/SYNC command you would write 0x80, 0x08 which is to issue a write to the device address 0x40 with the data 0x08 to issue the START/SYNC command.

    Best regards,

    Bob B