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MSPM0L1305-Q1: FCL function

Daria Kiseleva
Intellectual 2645 points
Part Number: MSPM0L1305-Q1

Tool/software:

Good day, colleagues,

1. If these two PIN pins are used as timer function. Is it necessary to increase pull-up resistance for them?

When the MCU is reset, these two PIN default output is high voltage or low voltage? What’s the value?

2. For the FCL function whether it is not necessary? If not used this function, that might have impact to the LIN2.1 baud rate synchronization?

Thank you,

Daria

  • 0
    TI__Expert 3430 points

    Hi,

    According to your questions，

    1. If it is not used for input or output, and is only used as an internal peripheral of the timer, then no external pull-up resistor is required.

    According to TRM 9.1.1 Website Link, all digital IOs controlled by IOMUX are in high impedance state by default after power-on.

    2. As described in the TRM, FCL is used to improve the crystal oscillator accuracy, it is recommended to use it if possible. But even without FCL, it is still able to meet the baud rate synchronization needs of LIN2.1 as responder mode (not commander mode). The following picture shows the LIN specs and the crystal error of MSPM0L Series.

    Best Regards,

    Peter

  • 0 in reply to Peter Jiang
    TI__Intellectual 2645 points

    Hi Peter,

    They need to use these pins (PA0 and PA1) as output for PWM and not only for internal timer, do you think it is possible  can output high level voltage without any external resistor?

    Due to PA0 and PA1 are default set to open drain,  if no other pull-up resistor , these two Pin can’t output the PWM signal correctly.

    Even though the configuration can set to pull-up resistor, but it looks like invalid.

    That means if they want to use PA0 and PA1 to the PWM output function, the external pull-up resistor is necessary. Correct?

    Thank you,

    Daria

  • 0 in reply to Daria Kiseleva
    Guru 42085 points

    Look at the input/output diagram:

    Note the note I highlighted. There is no internal pullup, an external one *must* be supplied.