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DAC81416: DAC81416

Akshay M R
Prodigy 50 points

Part Number: DAC81416

Tool/software:

Dear Sir/Madam,

We are having a problem while using DAC81416. We are trying to read its device ID and none of the time we are reading it. When we send a command to read Device ID as: 0x810000, the readback from DAC will be: 0x810000 i.e., we are getting echo of 1st byte, but not the device ID. We are using STM32H743BIT6 microcontroller and we also tried doing two access cycle i.e., 1st read command as 0x810000 and again sending a dummy command as 0x1DFFFF, but we are not able to read device ID. Can someone give a solution for this?

  • 0
    TI__Mastermind 42253 points

    Hi Akshay,

    Sanjay will review and get back to you with some suggestions soon. 

    Best,

    Katlynne Jones

  • 0 in reply to Katlynne Jones
    TI__Guru 57273 points

    Akshay,

    Can you see if you can read from any register? For example, can you try reading the SPI Configuration register?

    Can you confirm that your SPI phase and polarity are correct? Please capture the two commands with an oscilloscope or logic analyzer and we can confirm the edge relationship.

    thanks,

    Paul

  • 0 in reply to Paul_Frost
    TI__Expert 6550 points

    Hi Akshay,

    Adding to the Paul's comment, please check the digital IO levels and an the digital patterns along with the rest of the power supplies for the DAC81416.

    Thanks,
    Sajnay

  • 0 in reply to Paul_Frost
    Prodigy 50 points

    Paul, whatever register we are trying to read, we are getting the echo for 1st byte i.e., the read bit, dummy bit and address. But, the 16 bit data is as follows: 0x0080. 

    Regarding phase and polarity: Our microcontroller transmits on rising edge and receives on falling edge. Whereas the DAC receives the data on falling edge and transmits on rising edge. This means, our pol = 0 and phase = 1.

  • 0 in reply to Sanjay
    Prodigy 50 points

    The supplies are all building properly. Also, if power is the problem then we shouldn't have received the first byte correctly. But, that is coming as expected. 

    One more clarification, before communicating with DAC, should we write some non-zero character to NOP register. Also, if we have to read any register, do we have to send commands two times?

  • 0 in reply to Akshay M R
    TI__Expert 6550 points

    Hi Akshay,

    Let's debug this step by step, please check these details.
    1. measure the power supply values for VAA, VDD, VIO, VCC and VSS, report the voltage values. And check the datasheet to ensure the values are within limits.
    2. Capture the SPI lines on the scope and send the read command data for any readable register.

    Please do these first and then we will debug further.

    Thanks,
    Sanjay