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MSP430F6779A: Can the AUXKEY be written during LOCKAUX is set?

Part Number: MSP430F6779A


Can the AUXKEY be written during LOCKAUX is set? (to configure the AUXCTL2 as code below)


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AUXCTL0_H = AUXKEY_H;
AUXCTL2 = (AUXMR_0 | AUX0LVL_6 | AUX1LVL_5 | AUX2LVL_0);
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

  • Part Number: MSP430F6779A

    Are there other cases that LOCKAUX will be locked without reset?

    with our system found sometimes (rare cases) the LOCKAUX locked without reset after call the pmm api

    below

    PMM_setVCore(PMM_CORE_LEVEL_3);

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    uint16_t PMM_setVCoreUp ( uint8_t level){
    uint32_t PMMRIE_backup, SVSMHCTL_backup, SVSMLCTL_backup;
    //The code flow for increasing the Vcore has been altered to work around
    //the erratum FLASH37.
    //Please refer to the Errata sheet to know if a specific device is affected
    //DO NOT ALTER THIS FUNCTION
    //Open PMM registers for write access
    HWREG8(PMM_BASE + OFS_PMMCTL0_H) = 0xA5;
    //Disable dedicated Interrupts
    //Backup all registers
    PMMRIE_backup = HWREG16(PMM_BASE + OFS_PMMRIE);
    HWREG16(PMM_BASE + OFS_PMMRIE) &= ~(SVMHVLRPE | SVSHPE | SVMLVLRPE |
    SVSLPE | SVMHVLRIE | SVMHIE |
    SVSMHDLYIE | SVMLVLRIE | SVMLIE |
    SVSMLDLYIE
    );
    SVSMHCTL_backup = HWREG16(PMM_BASE + OFS_SVSMHCTL);
    SVSMLCTL_backup = HWREG16(PMM_BASE + OFS_SVSMLCTL);
    XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

    I think it's set because the voltage drops during the vcore change api, right?

    What conditions the MCU detected core power down and the set the LOCKAUX bit?

  • Hi Tink,

    AUXKEY will need to be written with enabling the LOCKAUX bit, so in your first line I would replace the AUXCTL0_H to just AUXCTL0 so you can set the LOCKAUX bit as well.

    LOCKAUX can be set after a BOR or when recovering from an LPMx.5 low power mode. Is your voltage dropping too low that you're triggering a BOR? Or are you using any LPMx.5 modes? (LPM3.5 or LPM4.5) 

    Regards,
    Luke

  • Hi Luke, 

    No,  I do not use the LPM 3.5 and LPM 4.5 and the BOR is not occurred.

    I debugged the source code before line 112 LOCKAUX  is clear. but after line 113 LOCKAUX  is set.

    Do you think AUXKEY be written during LOCKAUX is set may cause unexpected result? (in rare cases that i found)

  • Hi Tink,

    Can you check the SYSRSTIV register to see if there was a POR that got triggered? There are a couple of erratas related to false POR activation (PMM18 and PMM20). I want to verify that we aren't accidently hitting those erratas which is causing a reset to lock the AUX.

    (User's guide for your convenience: MSP430F6779A User's Guide

    Regards,
    Luke

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