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    help a bit confused about bitbanding

    • blakehew
      Posted by
      on Sep 05 2008 18:46 PM
      Prodigy20 points
      I'm wondering why

      Buttons = GPIOPinRead(GPIO_PORTE_BASE, GPIO_PIN_0);

      Works but

      Buttons = HWREGBITW(GPIO_PORTE_BASE, 0);

      Doesn't?

      What am i doing wrong in the second statement?

      Thanks.
      Report Abuse
    • jrmymllr49452
      Posted by
      on Sep 07 2008 07:15 AM
      Expert2110 points
      I don't have DriverLib readily available to me right now, but have you checked the source code to see what actually occurs when you use that function? The file should be gpio.c or something like that. You'll be able to easily see what the GPIOPinRead function is doing underneath.

      Post edited by: jrmymllr, at: 2008/09/07 07:15
      Report Abuse
    • slandrum
      Posted by
      on Sep 08 2008 12:01 PM
      Mastermind9510 points
      Bit banding is built into the GPIO register set. You don't want to use the bit-band macros.

      If you dig up the source for GPIOPinRead, it says:
      Code:


       long
      GPIOPinRead      (unsigned long ulPort, unsigned char ucPins)
      {
          return(      HWREG(ulPort + (GPIO_O_DATA + (ucPins <>2))));
      }





      From which you can make the obvious macro to do the same.
      Report Abuse

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