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DS90UB954-Q1: Parity check and CRC error

Tomoaki Yoshida91
Genius 5255 points
Part Number: DS90UB954-Q1


Hi team,

I have some questions about the behavior when a parity error and CRC error are detected.

#1

When a parity error is detected on the forward channel, is the data output from the CSI port or discarded?

I understand that the data is discarded only when the next registers setting is done, otherwise data is output, but is this correct recognition?

・PORT_PASS_CTL.PASS_PARITY_ERR and PORT_PASS_CTL.PASS_DISCARD_EN are set to 1

#2

When back channel CRC error or forwatd channel CRC error is detected, will the data be discarded at 953?

Best regards,

Tomoaki Yoshida

  • 0
    TI__Genius 12705 points
    Hello,
    1. Yes this is correct. By default the 954 is not set to truncate CSI packet transmission when PASS error is detected PASS_DISCARD_EN = 0. When PASS_DISCARD_EN = 0 the PORT_PASS_CTL register is set to include parity errors PASS_PARITY_ERR = 1, the CSI packets will not be forwarded once parity error is detected.
    2. Data over the backchannel will be ignored in case of back channel CRC errror. The 953 will only take action on forward channel CRC error from CSI-2 packets as described in the datasheet.
  • 0 in reply to Liam Keese
    Genius 5255 points
    Hi Liam-san,

    Thank you for your support.

    I understand.

    What happens to the output if a BCC back channel CRC error is detected and that data is ignored at 953?
    For example, if GPIO data was being transferred but a CRC error is detected, will the GPIO output be held in the previous state or fixed to Low?

    If a CRC error is detected on BCC's forward channel at 954, has 954 discarded this data?
    If BCC forward channel error is detected, BCC_CRC_ERROR sets 1 and interrupts are set by 0xD8[0] IE_BCC_CRC_ERR
    When interrupt have not set, will data to I2C output and GPIO output been discarded?

    Best regards,
    Tomoaki Yoshida
  • 0 in reply to Tomoaki Yoshida91
    TI__Genius 12705 points
    Yes, for back channel error occurring the transaction is interrupted and data will not be processed at 953. the state will remain until valid change in GPIO state is detected. Linked GPIO data is sent continuously, not just on transitions.

    Setting interrupt on 954 does not change how the data is processed, only whether it is flagged as interrupt or not.

    If you have new questions about 953-954 please start different E2E thread.
    Thank you,
    Liam