I am using AT89c2051 to multiplex 4x7 segments by configuring P3 as buffer for segments and P1.0~P1.3 as control bits for segments,two switches also connected at P3.0 and P3.1, I used the timer interrupt for multiplexing but i failed to use switches because thats are connected at same port which is being used for buffer for segments.Can anyone tell me how to use switches when using timer interrupt.
i failed to use switches because thats are connected at same port which is being used for buffer for segments I guess that the above means that you need to do this
instead of "do to P3" "do to P3shadow" mov p3,P3shadow
another method would be anl P3,# mask for bits not to be changed orl P3,# bits to be changed Erik
Thanks Eric for your kind giudeline to my problems's solution,whould you like to tell me more about the "shadow register" with examples.
Amjad
I DID give you an example
Erik