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MSP430FR5859: MSP430 resets at 1.8V with DCO 1Mhz

Gary Bloomfield
Prodigy 100 points
Part Number: MSP430FR5859

Greetings,

At startup the MSP430FR5859 runs at 2.1V in active mode - no problem.

After startup, the CPU supply voltage is switched from 2.1V to 1.8V.  When the supply voltage ramps down (about 7ms later) to about 1.81V the processor resets before it gets to 1.8V.  The CPU will run at 1.82V, but below that I get a reset.  Is there a way to disable the low-side SVS for this processor, or should I try to solve the problem a different way?

The problem happens with the MSP FET tool and in stand-alone release mode.

  • 0
    TI__Genius 15370 points

    Hi Gary,

    The minimum voltage is determined by the SVS level. As can be seen in Table 5-2 of MSP430FR58xx Mixed-Signal Microcontrollers, the power-down level can vary between 1.75 and 1.85V with a typical value of 1.8V:

    Unfortunately the SVS module on the MSP430FR5859 does not have programmable thresholds and cannot be turned off in active mode. The only time it can be turned off is in  LPM3, LPM4, LPM3.5, and LPM4.5 by resetting the SVSHE bit. 

    Best regards, 

    Caleb Overbay

  • 0 in reply to Caleb Overbay
    Prodigy 100 points
    Thanks for the response Caleb. It looks like the table says that the CPU will shut down if the supply voltage drops down anywhere between the 1.75V and 1.85V range. However, the 5859 datasheet says that it will work from 1.8V to 3.6V. Does this mean that if the supply voltage is 2.1V, I can only lower it to 1.86V without fear of reset? And, the 1.8V in the datasheet operating range is really 1.86V?
  • 0 in reply to Gary Bloomfield
    TI__Genius 15370 points

    Hi Gary,

    I'm assuming you're referring to Section 5.3 of the datasheet where is says the minimum operating voltage is 1.8V:

    This 1.8V is the nominal voltage and as can be seen from footnote 4: "The minimum supply voltage is defined by the supervisor SVS levels. See Table 5-2 for the exact values." This is what I was referring to in my previous post. So while the nominal operating voltage is 1.8V the actual voltage can vary from 1.75V to 1.85V. I recommend keeping the voltage equal to or greater than 1.86V.

    Best regards, 
    Caleb Overbay

  • 0 in reply to Caleb Overbay
    Prodigy 100 points
    Thanks Caleb. That answers my question.

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