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MSP430 flipping I/O bits

abhishek Sabnis
Expert 1730 points

Other Parts Discussed in Thread: MSP430F2132

We are using Ti's MSP430F2132 in noisy environment. One of the I/O pin is configured as a output pin with pull up disabled on it. During operation of our circuit this I/O is fliping its  output (from 0V- 3.3V) and remains in that state unless processor resets. But the software still runs and does its other activities during fliping state. Now if in software i check flipping bit every 1 sec and write 0 to to it, it works and I/O moves to its 0 state. 

If anybody know how to avoid this flipping of bit  please let me know.

Thanks,

Abhishek

  • 0
    Expert 1610 points

    Hi,

    this is interesting - since you configured your pin as output it should be driven to zero as long as the bit in PxDIR and PxOUT are not modified. Can you debug to verify if the contents of these two registers are modified. If the noise is really your problem you should care about some emi/esd precautions - a single bit flip is the harmless effect. Complete failures could also occur, which might cause more problems. Is only this single bit affected? 

  • 0 in reply to Jan Kesten
    Expert 1730 points

    Hi Jan,

    Actually, i am seeing 2 bits flipped in the noisy condition. PxDIR is not getting modified anywhere in software.

    But PxOUT is getting modified in one of the loop "A" as P1OUT |= BIT1.  But the control (when bit is flipping)  is inside another loop "B" and it should retain

    its state to P1OUT |= BIT1.

    The solution i did on this in software is, continous write P1OUT |= BIT1 when it is in loop "B".

     Also noise condition is occurs when Mains switch flipped continously.

    Regards,

     

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