PASM single pin turn on or off.

TJHJ · 2008-09-26 03:44

I dont know why I am having such a hard time with this. I am new to PASM( In case you missed that LOL). And I cant seem to find an example.

So I cant seem to figure out how to turn on or off a single pin. If I use the mov command, I overwrite the whole register. If I use an or command I cant garentee which state it is in.

Anyone have an example of how to do this.

Thank you for your time.

TJ

Mike Green · 2008-09-26 03:58

To turn on a pin (set it to 1), use OR. To turn off a pin (set it to 0), use ANDN. They can both use the same bitmask. For example:

               OR      OUTA,bitmask   ' This turns the pin on

               ANDN OUTA,bitmask   ' This turns the pin off

bitmask   LONG   |< 16              ' Have a single bit turned on (1).  The rest are zeroes.

The above assumes that the corresponding bit in DIRA has been turned on already.

TJHJ · 2008-09-26 05:08

Thanks mike, I was trying way to hard at this

TJ

StefanL38 · 2008-09-26 13:46

Hello TJ,

take a look at the PASM-commands MUXC MUCNC MUXZ MUXNZ Prop-manual page 383ff.

short example:

              mov       _dummylong, #0 wz               'load zero-value => Z-Flag=1
              muxz      DirA, _Bit                      'set the bit 


'define a constant at the bottom of the PASM-code 
_Bit              long |< 22 'create Bitmask where only bit 22 is set

best regards

Stefan

PASM single pin turn on or off.

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