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TMS570LC4357: IOMM Functionality

Part Number: TMS570LC4357

Hello,

We are currently using the TMS570LC4357 and we have some questions about the IOMM function.

- We do not find the information about the behaviour when signal or terminal is configurable both by the input multiplexing and the output multiplexing.Could you tell us more about this ?

- Since there is a default value on Input and Output multiplexing (i.e. IOMM always activated):

What the the behaviour if we use a pin as output (configured via output multiplexing) whereas the pin is also configurable via input multiplexing?

What the the behaviour if we use a pin as input (configured via input multiplexing) whereas the pin is also configurable via output multiplexing?

- Since there is a default value on Input and Output multiplexing (i.e. IOMM always activated),

what is the behaviour in the IOMM module if a pin configurable via input ou output multiplexing is used as GIO ?

Is the IOMM configuration performed once the pin is in GIO mode ?

Best regards,

Christopher

  • Hello Christopher,
    I have forwarded your question to one of our experts in IOMM.

    Best regards,
    Miro
  • Hello Christopher,

    The input multiplexing and output multiplexing use different control registers, so they can be configured independently. For example, GIOA[2] can appear on two different terminals at terminal number C1 and B15. By default PINMMR24[8] is set and PINMMR24[9] is cleared to select C1 for providing GIOA[2] to the system. If the application choose to use B15 for providing GIOA[2] then PINMMR24[8] must be cleared and PINMMR24[9] must be set.

    WHen GIOA[2] is configured as an output pin in the GIO module control register, then the programmed output level appears on pin C1 by default. The PINMMR19[0] is set by default to indicate that the GIOA[2] is selected to be output.

    If the application must output eQEPI1 signal on pin C1, it must clear PINMMR19[0] and set PINMMR19[5]. The eQEPI1 signal is also fed into multiplexer controlled by PINMMR24, then into GIOA module. In this configuration, GIOA[2] can be used to monitor eQEPI1.

    The application can choose terminal B15 as GIOA[2] input (PINMMR24[9] is set, PINMMR24[8] is cleared), and output GIOA[2] signal to terminal C1 (PINMMR19[0] is set).

    Yes, your understand is correct. The IOMM configuration performed once the pin is in GIO mode if it is configured as GIO.
  • Hello,

    Thansk four your answer.

    What is the beahviour of IOMM (registers including) if there is a bad configuration or inconsistent configuration:

    e.g: if N2HET2[16] in pin V7 is configured in Input via setting PINMMR98[1] (PINMMR98[0] is cleared) and at the same time, the pin V7 is multpilexed to N2HET1[9] via setting of PINMMR30[8].

    More generally, what is the behaviour of output multiplexing  if we configure input multplexing and what is the behaviour of input multiplexing  if we configure output multplexing.

    Best regards,

    Christopher

  • Hello,

    Do you have an answer to my question ?

    Regards,
    Christopher
  • Hello Christopher,

    The input multiplexing and output multiplexing can be configured at the same time. They are independent. As you know that the input signals are broadcast to all modules hooked up to a terminal. The application must ensure that modules that are not being used in the application do not react to a change on their input functions.