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Clarification on SYS12 Issue in MSP430F541xA/543xA Errata

A. Kirchhoff
Intellectual 535 points

The MSP430F541xA/543xA Errata describes the following issue:

SYS12 System Module

Function Invalid ACCVIFG when DVCC is in the range of 2.4 V to 2.6 V
Description A Flash Access Violation Interrupt Flag (ACCVIFG) may be triggered by the Voltage
Changed During Program Error bit (VPE) when DVCC is in the range of 2.4 V to 2.6 V.
Although this behavior is expected according to the user's guide, the VPE does not
signify an invalid flash operation has occurred.
If the ACCVIE bit is set and a flash operation is executed in the affected voltage range,
an unnecessary interrupt is requested. The bootstrap loader also cannot be used to
execute write/erase flash operations in this voltage range, because it exits the flash
operation and returns an error on an ACCVIFG event.
Workaround None

Could someone clarify what the micro's operation would be with Vcc in the 2.4-2.6V range and outside of that range?

I can think of two options and I don't know which is true.

Option 1:  The VPE bit may be incorrectly set when Vcc is in the 2.4-2.6V range when programming the Flash and causes the ACCVIFG bit to be set as intended.  Outside of that voltage range, the VPE bit works correctly and continues to cause the ACCVIFG bit to be set.

Option 2:  When Vcc is in the 2.4-2.6V range, the VPE bit causes the ACCVIFG bit to be set.  When Vcc is outside of that range, the VPE does not cause the ACCVIFG bit to be set.

Thanks, Austin

  • 0
    Guru 227245 points

    Option 1 is right.
    VPE might be signalled even if the voltage didn't change (and therefore VPE shouldn't be set at all), and while the programming was performed correctly.

    My guess is that it is a quirk in the programming voltage generator that possibly has a weak spot within in this voltage range. But that's just a guess.
    However, below 2.4V and above 2.6V, VPE is only flagged when indeed Dvcc has changed significantly during programming and the flash is possibly improperly written.

  • 0 in reply to Jens-Michael Gross
    Intellectual 535 points

    Jens-Michael,

    Thanks for the clarification.  I understand now.

    Austin

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