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MSP430FR2355: Start-up time at power-on

Koichiro Tashiro
Mastermind 22945 points

Part Number: MSP430FR2355

Hi,

My customer is asking how long does it take to execute the 1st instruction from power-on.
What customer understood are below.

If an external crystal is used:
[Power supply ramp time] + [crystal stabilization time] + [CPU internal delay]
If an internal clock is used: 
[Power supply ramp time] + [internal clock stabilization time] + [CPU internal delay]

Questions:
Q1) Are customer understandings are correct?
Q2) Customer guesses the [CPU internal delay] is equal to tWake-UP-RESET in datasheet Table 5-2.
Is this correct? If so, what is the MAX value?

Q3) If the answer to Q2 is "No", what is the [CPU internal delay] ?

Thanks and regards,
Koichiro Tashiro

  • 0
    TI__Mastermind 41940 points

    Hi Koichiro,

    For the device power up is ways using the internal clock first and switch it to external clock in application code. When the power supply to the valid value the device will start running the boot code in the boot code it will do some calibration and reset of the system and then jump to main function. The 1m you mentioned is the reset signal is the time to running the boot code. But for the power supply ramp time is related with external circuit of the capacitor values on VCC. I also not find the maximum value of the reset time, maybe you can use a GPIO toggle event at the beginning of the code to show it start and measure the start time.

  • 0 in reply to Gary Gao
    TI__Mastermind 22945 points

    Hi Gary,

    Thanks for your quick reply.

    Gary Gao said:
    The 1m you mentioned is the reset signal is the time to running the boot code.

    If I understood correctly the 1msec is the period the boot code is running. So it is always the same, right?
    Is there any cases the period get longer or shorter?

    Gary Gao said:
    I also not find the maximum value of the reset time, maybe you can use a GPIO toggle event at the beginning of the code to show it start and measure the start time.

    Customer is asking for the worst case, so just checking a few samples does not answer the question.
    Again, if the 1msec is code running time, it should be no min/typ/max differences.

    Thanks and regards,
    Koichiro Tashiro

  • 0 in reply to Koichiro Tashiro
    TI__Mastermind 41940 points
    Koichiro Tashiro said:
    So it is always the same, right?

    I think so.

  • 0 in reply to Gary Gao
    TI__Mastermind 22945 points

    Hi Gary,

    I see. Thanks.

    I have two more questions from the customer.
    What are the maximum values for below two parameters?

    #1: DCO FLL lock time


    2) REFO startup time


    Thanks and regards,
    Koichiro Tashiro

  • 0 in reply to Koichiro Tashiro
    TI__Mastermind 41940 points

    Hi Koichiro,

    We don't have such specific maximum values for DCO FLL lock and REFO startup time. But I just can provide some results based on our test data that we don't find the any test device CO FLL lock time > 220ms and REFO startup time >95us. 

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