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AM2434: Reset by MCU_PORz without power-up

Daisuke Maeda
Guru 20205 points
Part Number: AM2434

Reset by MCU_PORz can be done with or without power-up.

What is the difference in effect of the reset by MCU_PORz with and without power-up?

Best regards,

Daisuke

  • +1
    TI__Guru*** 135355 points

    Hello Daisuke-san,

    It's not so much a difference in effect as much as a difference in usage.

    When powering up, PORz needs to be held low until all supplies are valid and the crystal oscillator has stabilized. This is a specific case to going from a power down scenario to power up. Holding PORz low is required to keep the MCU core in reset until all power supplies and the crystal oscillator are operating as required for the MCU to function. This scenario is not a 'reset by PORz with power up' but rather the 'usage of PORz as part of the proper power up sequence'.

    Outside of powering up the device, PORz can be used to trigger a cold reset of the MCU. In this scenario, no power rails nor the crystal oscillator would have any change in functionality, but PORz would be pulled low to trigger a cold reset of the MCU core.

    Best Regards,

    Ralph Jacobi

  • 0 in reply to Ralph Jacobi
    Guru 20205 points

    Hi Ralph-san,

    Thank you for your reply.

    Ralph Jacobi said:
    It's not so much a difference in effect as much as a difference in usage.

    Is there not any difference in effect?

    Is the state the same after a proper power-up sequence and after a cold reset triggered using MCU_PORz?

    Best regards,

    Daisuke

  • +1 in reply to Daisuke Maeda
    TI__Guru*** 135355 points

    Hello Maeda-san,

    Daisuke Maeda said:
    Is the state the same after a proper power-up sequence and after a cold reset triggered using MCU_PORz?

    Correct it would be at the same state afterwards. POR is a Power-On-Reset so it is meant to provide the same conditions after a successful power on sequence.

    All I/O will be set to default states and, if applicable via SOP pins, the SBL will execute just like initial device power on.

    Best Regards,

    Ralph Jacobi