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MSP430G2553: MSP430G2x53 - minimum VCC vs max speed for execution and flash erase/write

O'Mellin
Expert 5755 points
Part Number: MSP430G2553

Team,

I have doubts on the way figure 1 of the datasheet (safe operating area) should be understood:

my customer operates at 3.3V 16MHz and has flash corruption problem. He's investigating if slight drops on Vcc can happen.

If Vcc drops at 3.2V operating at 16MHz:

- do we guarantee CPU execution?

- do we guarantee flash write/erase?

thanks

  • 0
    TI__Expert 5755 points

    Part Number: MSP430G2553

    team,

    Is there a constraint of vcc min vs Fftg max or can customer program the ISP the way she/he like withing Vcc 2.2/3.6V - Fftg 257/476KHz ?

    thanks

  • 0
    Guru 74080 points

    Hi!

    According to the datahseet, the minimum supply voltage for 16MHz is 3.3V - if you cannot maintain 3.3V, running the device at 16MHz might not be the best idea, although I think that it will work at 3.2V, but the datasheet is the document to stick to when designing serious electronics. However, the flash write works down to a supply voltage of 2.2V, so no problem here. What is your customer's prescaler for the flash controller clock?

    Dennis

  • 0
    Intellectual 820 points
    I saw something like this a few years ago (not a TI MCU). We solved it by slowing the clock down for the duration of the flash write cycles. Maybe not the best answer, but it worked so other possible solutions were not investigated.
  • 0 in reply to Jeff Hastings
    TI__Guru 56685 points
    Hello O'Mellin,

    I've merged your two posts as they are about the same subject. You need a minimum of 3.3V to operate at 16MHz for this device. Any drops in VCC will cause the MCU to operate out of spec with unpredictable results. If you are trying to write to flash during one of these dips, flash corruption is very likely. As suggested, if you cannot guarantee a minimum 3.3V supply while operating at 16MHz, then you will need to lower your clock frequency.
  • 0 in reply to Jace H
    TI__Expert 5755 points
    Thanks JH,

    this answers my question on VCC vs. Mclk and usage being out of spec, thanks.
    Then specifically about flash corruption I would expect a limitation vcc vs Fftg as the flash is not clocked by Mclk necessarily. would you have data on this?

    thanks
  • 0 in reply to O'Mellin
    TI__Guru 56685 points
    O'Mellin,

    the Flash maybe clocked separately, but if your core is being operating in an undefined state, what is be written and where it is being written could be undefined as well. The Frequency vs Voltage violation affects core voltage levels and thus registers and the PC counter can be corrupted.
  • 0 in reply to Jace H
    TI__Expert 5755 points
    JH, thanks.
    this is clear, but if VCC vs. Mclk is respected, is there Vcc vs. Fftg conditions that needs to be respected beyond sitting within Vcc 2.2/3.6V - Fftg 257/476KHz?
    thanks
  • 0 in reply to O'Mellin
    TI__Guru 56685 points
    For Flash timing vs VCC, you just need to be above 2.2V.

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