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TMS570LC4357: Documentation inconsistency between Reference Manual and Datasheet

Gael Le Moing
Expert 1020 points
Part Number: TMS570LC4357

Hi,

I am using a TMS570LC4357 package ZWT and I want to use MIBSPI2NCS[1] (pin D3 only).

I configured the output multiplexing register PINMMR35[13] as indicated in table 4-28 in the datasheet / table 6-1 in the TRM.

But I was confused then as I found the same pin configurable also for input multiplexing in table 6-2 of the TRM.

In the Reference manual, table 6-2 indicates that MIBSPI2NCS[1] is available on D3 pin if PINMMR88[17] = 1.

In the Datasheet, table 4-29, the MIBSPI2NCS[1] is not listed in the same table.

My questions are:

- Which input pin multiplexing table is applicable?

- if the table from the TRM is applicable, then do I need to configure the PINMMR88 if I use this pin for SPI communication, and why? Would the answer be different if I was using the MIBSPI2NCS[1] pin as a GPIO input? GPIO output?

Best regards,

Gael

  • 0
    TI__Guru**** 196776 points
    Hello Gael,

    Please use the table 4-29 in datasheet (spns195c). The table in TRM says the 1st option is NA (not applicable). MibSPI2CS[1] is connected to only one terminal: D3.
  • 0 in reply to QJ Wang
    Expert 1020 points
    Ok, thank you for your answer.

    More generally, if I write to a PINMMR registers in 32-bits, does the value written in a field that is not shown in the table (4-28 or 4-29 in datasheet) matters?
    Example: PINMMR37[16-23], PINMMR37[24-31], PINMMR89[0-7], PINMMR89[8-15]

    Thanks
  • 0 in reply to Gael Le Moing
    TI__Guru**** 196776 points
    Hello Gael,

    It doesn't matter. Only bit 16/17/24/25 of PIMMMR89 are used. Writing to other unused bits will have no effect.
  • 0 in reply to QJ Wang
    Expert 1020 points
    Hi,

    I performed a check on a board and if I don't configure the PINMMR88 register for the input path the MIBSPI2NCS[1] doesn't indicate the state of the D3 pin (I configured this pin as a GPIO pin to be able to manipulate it via the SPIPCx registers of the MIBSPI module).
    So I guess now that the table for Input multiplexing in the TRM should be taken into account instead of the one found in the Datasheet.
    I don't use the eCAP and eQEP modules, but the TRM also indicates that by defaut eCAP and eQEP inputs are mapped to no pin and the application needs to configure it before using these modules (the Note comes from chapter 6.4 of TRM).
    Do you agree with that?
    Thanks
  • 0 in reply to Gael Le Moing
    TI__Guru**** 196776 points
    Hi Gael,

    I agree with you.
    if you use MibSPI2NCS[1] as input (gio mode), the pinmmr88[17] has to be set.

    For eCAP and eQEP, they can not be used as input, the table 4-29 looks ok. But it is better to add ecap and eqep to table 4-29 as in table 6-2 in TRM.

    Thank you Gael