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MSP430F149 doesn't reset.

Remony
Expert 1560 points
Other Parts Discussed in Thread: MSP430F149

Hi,

Sometimes MSP430F149 froze on my board.

Reset pin of F149 is connected with output of reset IC as below image.

F149 makes the pulse during operation to the WDI of reset IC.

If F149 froze, reset IC makes the reset signal to MSP430.

But MSP430 don't reset.

If MSP430 holds POR state, a low signal on the RST/NMI pin can reset?

During the POR, What is the status of RST/NMI port?

  • 0
    Guru 74080 points
    Hi Remony!

    Can you find out where your processor freezes? This could be a programming fault somewhere in your code - have you tried to flash a basic program to the MSP, only running a very small application to feed the MAX6864's watchdog, just to ensure the problem is not hardware related? Did you disable the MSP's watchdog?

    Dennis
  • 0 in reply to Dennis Eichmann
    Expert 1560 points

    Hi, Dennis,

    I have seen same problem before.

    At that time, the cause of problem is POR.

    VCC rise very slowly. I can't guarantee this time.

    So I applied the MAX6864 to solve this problem.

    If programming is the problem as you said, why doesn't MSP reset when the reset signal is generated by MAX6864?

    In addition my code has been released at field for a long time.

    So I review the hardware first.

     

    I'd like to know that if the MSP keeps in POR condition, can low signal on the RST/NMI pin reset MSP and regenerate POR?

  • 0 in reply to Remony
    TI__Intellectual 1330 points
    Hi Remony,
    for the MSP430F149 device is an errata entry (RES4) available about the reset circuit. It says that no RESET is performed if the external pull down resistor is above a certain limit. Based on you schematic, it looks like you running in this issue. Can you check this please?

    Errata description:
    Function No reset if external resistor exceeds certain value
    Description No reset of the device is performed if the external pull down resistor on RST/NMI pin is
    above a certain limit. The limits are:
    Vcc = 1.8V: maximum pull down resistor = 12 kohm
    Vcc = 3.0V: maximum pull down resistor = 5 kohm
    Vcc = 3.6V: maximum pull down resistor = 2.5 kohm
    In addition, a higher current consumption occurs during high/low RST/NMI signal transition when using improper resistors.

    Workaround:
    Use external pulldown resistors below the listed values or directly drive RST/NMI low to
    generate a reset.

    Best regards,
    Tobias

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