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MSPM0L1306: Behaviour of BOR0

Sourabh Devarmani
Prodigy 80 points
Part Number: MSPM0L1306

Tool/software:

  •  when VDD goes less than VBOR0- (1.58 v) then BOR is asserted.
  • When VDD goes above VBOR0+ (1.59v) to 1.62 then BOR is released and software is working. As per MCU data  sheet.

          

3) what is the behavior when VDD goes above from 1.62v to ~(3.3v - 3.9v)?  As per waveform it should be in running state. but as per my observation still MCU is in reset state.

Are the contents of SRAM guaranteed to be valid when VDD is in between 1.62 to 3.9v?

  • 0
    TI__Expert 7760 points

    Hello Sourabh,

    1). After VDD goes above 1.62 V, and then Vcore will start to rise to about 1.35 V. After that it will start to run the boot code in ROM and then to run the application code in Flash. Please check your Vcore voltage and the Cap value near Vcore and VDD;

    2). Please check the voltage on NRST pin;

    3). Our recommend voltage on VDD which can make MCU work normally is 1.62 ~ 3.6 V, why you need to add to 3.9 V?

    Best Regards,

    Janz Bai

  • 0 in reply to Janz Bai
    Prodigy 80 points

    1)

    i) Cap near Vcore is 470nF

    ii) Cap near VDD is 10uF and 100nF in parallel

    2) NRST pin is low after 1.62v

    3) In the voltage range 1.62 ~ 3.6 V MCU still in reset state. after ~3.9v to 4v MCU is getting ON. 

     

    Janz Bai said:
    voltage on NRST pin
  • 0 in reply to Sourabh Devarmani
    TI__Expert 7760 points

    Hello Sourabh,

    1). What is the meaning of "NRST pin is low after 1.62 v"? It means that NRST will be low after VDD raises to 1.62 V, or it means that NRST voltage is lower than 1.62 V?

    2). How do you judge that MCU is in reset state, observing something? 

    3). Our recommend voltage on VDD which can make MCU work normally is 1.62 ~ 3.6 V. The goal of rising VDD to 4.0 is just for tests or it is the requirement of your factual application? If you keep the VDD voltage at 3.3 V, the MCU will always in reset state?

    4). What is the voltage on Vcore in your test process?

    5). In fact, if NRST is high voltage and Vcore voltage is correct, and Cap near VDD and Vcore is correct, MCU must work normally at 3.3 V. Do you have MSPM0L1306 LaunchPad, you can download example code in SDK to M0 and check whether it can work normally. 

    Please help to confirm this points.

    Best Regards,

    Janz Bai

  • 0 in reply to Janz Bai
    Prodigy 80 points

    1) NRST pin is low low after VDD raises to 1.62 V

    2) Togging GPIO pin to judge that MCU is in reset state or not.

               if MCU is in reset state GPIO pin will not toggle after reset GPIO pin will toggle.

    3) Yes, when VDD voltage at 3.3 V MCU is in reset state.

    4) I will check the voltage 

    5) I don't have MSPM0L1306 LaunchPad. I am testing on custom board, which has LIN Transceiver connected to MCU 

  • 0 in reply to Sourabh Devarmani
    TI__Expert 7760 points

    Hello Sourabh,

    Why NRST is low? If it's pulled down to low, it will make MCU in reset state. Please check why the NRST is low after VDD raises to 1.62 V, and check the NRST voltage when the VDD is 3.9 V ~ 4 V. In fact, our MCU VDD can't set to 4 V because it may cause MCU work abnormally, but I want to know the NRST voltage when VDD is over 3.9 V. 

    So if you keep VDD 3.3 V forever, MCU will always in reset state, and GPIO will never toggle, right?

    In fact, I think maybe MCU has been broken when you raise VDD over 3.6V for many times.

    Best Regards,

    Janz Bai