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HTU DCP RAM Parity Error when CPU reads the DCP RAM and HTU EN Bit is ZERO



Hello Support,

In the HTU GC Register, when HTU EN Bit is ZERO,  HTU PCR Register PARITY_ENA = 0x0A, then is there any possibility of Parity Error [ESM Channel 8] when CPU Read DCP RAM assuming there is Parity Error already present with DCP RAM Area?

Or, Parity Error is not enabled to ESM Module Channel 8 if HTU EN Bit = ZERO in HTU GC Register.

Is there any relation between HTU Parity Error to ESM Channel 8 connection with HTU EN Bit of HTU GC Register?

Any information about the inter-relation between HTU Parity Error, ESM Channel 8 and HTU EN Bit will be helpful for case where CPU is the Master reading from DCP RAM with Parity Error present within DCP RAM.

Thank you.

Regards

Pashan

 

 

  • Hello Support,

    For the above mentioned condition assume ESM Group 1 Channel 8 is enabled for HTU RAM Parity Error within ESM Module Setup Register.

    Also assume that HTU DCP RAM have already Parity Error bit as wrong.

    Thank you.

    Regards

    Pashan

     

  • Pashan,

    Any RAM read triggers HTU Parity errors if the PARITY_ENA is not 0x5 (i.e parity is enabled); this includes CPU reads.  The signal to the ESM cannot be masked in the HTU so the ESM will see the HTU error signal.

    Best Regards,

    Forum Support

    "During a read access to the DCP RAM, the parity is calculated based on the data read from the RAM and compared with the good parity value stored in the parity bits. The parity check is performed when the HTU or any other master (for example, CPU) makes a read access to the DCP RAM."  21.2.6 from SPNU499A