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DAC8760: Frame Error Checking

Hisao Uchikoshi
Genius 14880 points
Part Number: DAC8760

Hi Experts,

When enabling Frame Error Checking by setting CRCEN bit to 1 of Configuration register, are all register access listed on table 18 required 24bit + 8bit CRC? Or, does only write to DAC Data register require CRC bits from host processor?

regards,

Uchikoshi

  • +1
    TI__Guru* 97775 points

    Uchikoshi-san,

    When the CRCEN bit is set to 1, the command do require the 24-bit plus the 8-bit CRC. The device is checking for the 32 bits in the data frame. 

    However the DAC8760 does have some conditions the CRC is not checked for the correct CRC word. The following commands have the following behavior with the CRC error:

    For the following write commands, the CRC error status condition blocks the execution

    • 0x01 Write DAC Data register – CRC error does not execute command and sets ALARM
    • 0x55 Write control register – CRC error does not execute command and sets ALARM
    • 0x57 Write configuration register – CRC error does not execute command and sets ALARM
    • 0x58 Write DAC gain calibration register – CRC error does not execute command and sets ALARM
    • 0x59 Write DAC zero calibration register – CRC error does not execute command and sets ALARM

    For these commands, the CRC error status is not checked, and the command execution is not blocked

    • 0x56 Write reset register - Execute command even with bad CRC (reset is 0x56 0x00 0x01 0x5E)
    • 0x95 Watchdog timer reset - Execute command even with bad CRC
    • 0x96 CRC error flag reset - Execute command even with bad CRC
    • 0x02 Register read - Execute command even with bad CRC


    Joseph Wu

  • 0 in reply to Joseph Wu
    TI__Genius 14880 points

    Joseph-san,

    Thank you for your answer. It looks that 0x96 register does not exist on DAC8760.

    Thank you!

    Regards,

    Uchikoshi

  • +1 in reply to Hisao Uchikoshi
    TI__Guru* 97775 points

    Uchikoshi-san, 

    The 0x96 register should reset the CRC error. It is something that we are also adding to the datasheet. This originally was put in the device, but it was missed in the previous revisions of the datasheet. 

    Joseph Wu