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MSP430F2122: MSP430F2122

Intellectual 450 points

Replies: 4

Views: 263

Part Number: MSP430F2122

PROBLEM WITH I/O PORT 2...."BUG" ??

I have the following 2 port lines in use as follows:
P2.1  = OUTput sending a TTL signal level to an external part of the circuit  (BIS.B #BIT1,&P2DIR)

P2.2 = Analog input.  (BIC.B #BIT2, &P2DIR)+ ADC allowable input set to include A2 (=P2.2)

THE PROBLEM. When I set P2.1 to 'output'.... P2.2 is turned into a short, and my analog voltage disappears.

ERRATA I could not find any reference to this situation in the Errata file for the device.

My Schematic is attached.

  • The pins are known to work correctly. This is likely to be a problem with your software or your circuit.

    The schematic is incomplete; what are "PREREG" and "LoHiV" connected to? And what about P2.1?

    What do you mean with "short"? What does it appear to be shorted to? Ground?

    Please note that when A2 is configured, you do not need to clear the P2DIR bit (see table 23 of the datasheet).
  • Hi Julian,

    I second Clemens on his comments that the pins are known to work correctly. Could you share more details on the questions that Clemens posted?
    This might help us to understand what's going wrong for you.

    Thanks and best regards,
    Britta
  • In reply to Britta Ruelander:

    Hi Julian,

    has your issue been solved? Please note that I am going to close this thread in case I don't hear back from you. Let me know in case you need further assistance.

    Thanks and best regards,
    Britta
  • In reply to Britta Ruelander:

    PROBLEM WITH PORT 2.1 and 2.2

    Thanks for the contribution from Clemens and others. 

    FOUND IT.....  yes, it was a hardware issue. There was a very fine almost invisible solder bridge between the relevant pins on the PCB.

    Sorry to trouble you all, this issue is now RESOLVED... 

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