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MSP430FR2632: Startup Time

Ray Vincent Aranzaso
Mastermind 18180 points
Part Number: MSP430FR2632

Hi,

Good Day.

Customer need to know the time from powerup until the CPU is running, MSP430FR2632IYQWT.

He can't find anything in the datasheet or user manual.

He don't care about the ADC VREF.

If the Brownout / Reset circuit causes a delay, he need to know what it is.

Please advise. Thank you very much.

Best Regards,

Ray Vincent

  • 0
    TI__Guru 70506 points

    Hi Ray,

    The time it takes for the system to come out of reset (depending on the clock source) is small compared to the time it takes for the boot initialization code to run before even getting to the user's main().  What is the application and target powerup time for the customer?

  • 0 in reply to Dennis Lehman
    TI__Mastermind 18180 points

    Hi Dennis,

    Good Day. Please see below the response of our customer to your reply. Thank you very much.

    Assume that the boot code isn't allowed to run by holding the TEST pin low on powerup. What is the clock speed of the internal RC oscillator on power up? Does the powerup circuitry (brownout and reset) have a delay from powerup?

    Best Regards,

    Ray Vincent

  • 0 in reply to Ray Vincent Aranzaso
    TI__Guru 70506 points

    Hi Ray,

    Ok, if holding the device in RESET during power up then I believe there is an SVS delay (10us) plus the time for the DCO to startup (16us).    Does this help?

  • 0 in reply to Dennis Lehman
    TI__Mastermind 18180 points

    Hi Dennis,

    Good Day. Please see below the response of our customer to your reply. Thank you very much.

    It looks like the clock isn't a problem. The reference voltage for the brownout detect circuit usually take some time to stabilize. If I have the reset pin pulled up to VCC, and apply 3.3 volts between GND and VCC, is there an added delay period to come out of reset because of the brownout circuitry? I'm concerned about the tWAKE-UP-RESET time spec on page 28 of the datasheet (Rev E) and how it applies. I can't tolerate 1mS from power up until the MPU starts running instructions.

    Best Regards,

    Ray Vincent

  • 0 in reply to Ray Vincent Aranzaso
    TI__Guru 70506 points

    Hi Ray,

    The spec on page 28 is with the device powered on, but in a low-power mode and refers to waking the device from a low-power mode with either the RST pin or port interrupt and the time it takes to get to the first user instruction.  So the 1ms includes the internal boot code, which would be about the same amount of time required during a POR, and is actually pretty decent.  Other MSPs have startup times upwards of 10ms.  If the target is to have the MSP up and ready to execute code sooner than 1ms, I don't there is an MSP430 that will meet this requirement.

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