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TMS570LS1224: Need clarification on Nerror pin forcing Test

Bharat@Honeywell
Prodigy 180 points
Part Number: TMS570LS1224
Other Parts Discussed in Thread: HALCOGEN

Hello Team,

I am trying to implement error forcing on nerror pin as described in the TMS50LS1224 TRM (12.2.3 Forcing an Error Condition)

My concern is the point 2. contradicts to the figure 12-9.

 

As per the point 2. we need to write 5h to ESMEKR to force the nerror pin to low, whereas the figure 12-9 specifies write Ah to ESMEKR to force the nerror pin to low.  

Is this is a documentation issue?? which one should i follow? or did i misunderstood ??

Please clarify on this issue.

Regards,

Bharat

  • 0
    TI__Mastermind 49120 points
    Hi Bharat,

    Thanks for catching this documentation error. The error forcing mode is activated by writing 0xA to the ESMEKR, as shown in the figure.

    I will file a documentation bug report, so that it is addressed in the next update.

    Regards,
    Sunil
  • 0 in reply to Sunil Oak
    Prodigy 180 points
    Hello Sunil,

    Thanks for the quick update.

    what should we Write to the ESM Error Key Register (ESMEKR) back to the active normal mode.

    is it 0h or 5h??

    Point 3. of documentation tells to write 0h to ESMEKR, wheras in the halcogen generated code(esm.c) esmEnterSelfTest() function 5h to ESMEKR.

    Can you please clarify?

    Regards,
    Bharat
  • 0 in reply to Bharat@Honeywell
    TI__Mastermind 49120 points
    Bharat,

    Writing 0x0 will immediately take the nERROR pin high if there is no real group2 or group3 errors while the ESM was in error forcing mode. In general, however, you need to write 0x5 to the key register to reset the nERROR pin. Then the pin will go high after the low-time-counter expires.

    Regards,
    Sunil
  • 0 in reply to Sunil Oak
    Prodigy 180 points
    Hello Sunil,

    Thank you for the response.

    My intent was to force nerror pin, i am using the halcogen generated API(esm.c)
    esmEnterSelfTest()

    In this function, nerror pin was forced to active low by writing 0xAh to the key ESMEKR register. The nerror pin is brought back to normal mode by writing 0x5h to the key ESMEKR register.

    According to you it should go high after the low-time-counter expires, but during my observation it is going immediately. Can you cross check ??

    I verified the nerror pin behaviour in CRO by calling this API esmEnterSelfTest(), it is immediately going to high.

    can you please check and let me know.

    Regards,
    Bharat

    Can you please clarify?
  • 0 in reply to Bharat@Honeywell
    TI__Mastermind 49120 points
    Hi Bharat,

    The nERROR signal goes High immediately after writing either 0x0 or 0x5 when the ESM is in an error-forcing mode. If there is a real ESM group2 or group3 error, then the nERROR signal will go high only by writing 0x5 to the key register. In this case the LTC defines how long the nERROR will stay low before the ESM switches back to the normal operating mode.

    Regards,
    Sunil