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MSP430F47167 CPU doesn't work

Khue Tra
Prodigy 10 points
Other Parts Discussed in Thread: MSP430F47167

I am developing an application using msp430f47167. There are 50 samples for this application. all of samples that include cpu can work, however, some of them sometimes are out of order when i turn on power supply. My current power supply is 3.3V converted from 3-phase power. I have been performing all recommendations in the manufacture guide, but they still can not work.

Please help me !!! 
Thanks,
P/s : I'm using IAR compiler for msp430.

  • 0
    Guru 227245 points

    When turning on power, it will not instantly jump to 3.3V. Partly because the regulator needs some time to regulate (and is built to not overshoot), partly because of line impedance and blocking capacitor charging.
    When the brownout circuit releases the MSP for operation, the 3.3V are possibly not reached yet. And the code may do things that won't work with the still lower supply, causing the MSP to crash.
    Since the brownout circuit, as well as the internal reset delay, has some variation across MSPs, only part of your MSPs might be affected in your specific power environment.

    For this case, an R/C combo on the reset pin is used. To keep RST low (and the MSP in reset) while Vcc is still rising.
    Typically 47k to Vcc and 100nF to Vss are a good choice. (if the MSP shall be programmed using SBW, 2.2nF are the allowed maximum, but the 47167 doesn't support SBW anyway).

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