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SCI2 not working at all (wrong pins?)

ItKo
Prodigy 215 points


Hello,

I've been trying to get the SCI2 module on a TMS570LC43x HDK to work for quite some time now. However, I am getting no response from the Tx (pin T5) or Rx (pin P4) pins.

I've tried the following:

1) Sending a Tx signal: pin remains low.

2) Setting both Tx and Rx pins to GIO mode and initializing them as high output. Pins still remain low.

3) Setting both Tx and Rx pins to GIO mode and toggling the pins from high to low. Pins remains low the entire time.

4) Sending a Tx signal through SCI1. This works fine.

The SCI2 register seems to be working fine (pin value is registered correctly in PIO2 register and TD is updated with the next Tx byte). However, I don't actually see any physical output from the pins. This makes me think I am using the wrong pins.

I've verified that the SCI2 is enabled in the PINMUX (i.e. bit 1 and bit 9 are set). The behavior seems to indicate that I am using the wrong pins. I've tried nearby pins on the board, but am still getting no response. 

  • 0
    TI__Mastermind 22715 points

    Itto,

    I would suggest doing debugging in the following steps.

    (1) Make sure that those two pins are on the connector. By default, they are N2HET2[19] (P4) and N2HET2[20](T5). Make them as GIO output and toggle the level via the N2NHET2 control registers. You will need to enable N2NHET2 for doing this.

    (2) If (1) works as expected, check the pinmux for SCI2/LIN2. Check the values of LIN2/SCI2 registers at start address 0xFFF7_E600 to see if it is enabled.

    Thanks and regards,

    Zhaohong

  • 0 in reply to Zhaohong Zhang
    Prodigy 215 points
    I've begun doing #1 and the first thing I notice is that pins T5 and P4 are not triggered by NHET2[20] and NHET2[19], but rather they are tirggered by NHET2[28] and NHET2[27]. Basically, according to the datasheet, the pins are behaving as if they were pins R5 and P5. So it seems to be one of two cases:

    1) The pins are mislabeled on the HDK.
    2) The datasheet is incorrect in its pin descriptions.

    Now the question is, where are the pins for LIN2 (or SCI2) Tx and Rx?
  • 0 in reply to ItKo
    Prodigy 215 points

    I've looked into the schematics and board file. It doesn't seem that pins T5 and P4 are connected anywhere. The pins labeled as T5 and P4 seem to actually be R5 and P5. It therefore seems that the SCI2/LIN2 module is inaccessible.

  • 0 in reply to ItKo
    TI__Mastermind 22715 points
    Itto,

    The pin assignments (T5 and P4) is correct. They are open on TMS570LC43x HDK. The only way to access those two pins is If you really want to adding wires to the small holes in the back of the device on the board. Where did you probe them?

    Thanks and regards,

    Zhaohong
  • 0 in reply to Zhaohong Zhang
    Genius 4015 points
    Hi
    I have the same problem... but with another board... The TX pin works, fur when using the function getSetBit(linPORT,0x2,1)for the RX pin the value doesnt change. I already quadruple checked the configuration and the pin...