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TMS570LS1227: UART no output occasionally

Gary Jiang
Intellectual 980 points
Part Number: TMS570LS1227

Hi team,

My customer now finds a issue that TMS570 occasionally(during several days stability experiment) will encounter a issue that the UART TX has no output(voltage level is high or low is not recorded).

This uart(UART1) interfaces to a level shift chip then a 4G module, and another uart(UART2) is used to print out log. Occasionally UART1 TX will have no output(tested by oscilloscope) while the UART2 printed log indicates the APP is still running. Normally UART1 TX should output a package every 600ms.

They wonder what may cause the TX have no output? Power down and up the device then everything goes back to normal. 

Thanks 

Gary 

  • 0
    TI__Guru**** 186216 points

    Hello Gary,

    After UART1 TX stops working, did you check the pinmux setting for SCI1 (pin 38, 39) and SCI baudrate setting? Does the UART1 RX work? 

    You said that TX has no output? Did you probe the TX out at pin 39 or at the output pin of the level shifter or UART transceiver?

  • 0 in reply to QJ Wang
    TI__Intellectual 980 points

    Hi QJ,

    Sorry but is pinmux setting controlled by register PINMMR_0 to PINMMR_47? There are so many registers and I can't be sure.

    And why cares about SCI baudrate setting? I suppose even if they set up a wrong baudrate the TX still can output data. Besides, the fault happens during a long time running, I'm sure they will not change the baudrate while in the program. 

  • 0 in reply to Gary Jiang
    TI__Guru**** 186216 points

    Hello,

    1. SCITX and SCIRX are defined in PINMMR7 and PINMMR8

        pinMuxReg->PINMMR7 = PINMUX_PIN_37_MIBSPI3NCS_1 | PINMUX_PIN_38_SCIRX;
        pinMuxReg->PINMMR8 = PINMUX_PIN_39_SCITX | PINMUX_PIN_40_MIBSPI1NCS_2 | PINMUX_PIN_41_HET1_15;

    2. I'd like to know if the value of SCI baudrate register or PINMMR registers are changed during the code execution. 

    3. Can you check if the VCLK (configure ECLK to output VCLK, then probe the ECLK) is correct after the SCI stops working?

  • 0 in reply to QJ Wang
    TI__Intellectual 980 points

    Hi QJ,

    Thanks for your answer.

    Now my customer replies the followings:

    1. Their 570 application has sleep mode, and during long time test before this issue happens the 570 will enter sleep mode and can't use emulator to read the registers when the TX stops working;
    2. RX still works when TX stops, can we assume the baud rate is right?
    3. They probe the TX out at pin 39;

    Because this issue is really hard and time-consuming to reproduce, so they wonder if there are any other possibilities and they can test them with VCLK together.

    Thanks again for your help.

    Gary

  • 0 in reply to Gary Jiang
    TI__Guru**** 186216 points

    Hello Gary,

    Does this issue happen after the device enters the sleep mode? When the device is in sleep mode, the device is not able to TX message. The device can be waked up through GIO interrupt , CAN or SCI message. 

  • 0 in reply to QJ Wang
    TI__Intellectual 980 points

    Hi QJ,

    No, the device did not enter the sleep mode, because another set of UART is still work and can print out log info. So I suppose it's not the reason.

    Gary

  • 0 in reply to Gary Jiang
    TI__Guru**** 186216 points

    Hi Gary,

    Can you ask your customer to print out (UART2) the SCI1 registers' value (GCR0, GCR1, FLR, BRS, etc)?