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.
chaokhun.kmitl.ac.th/.../clock.htm
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 Andy Neil for your kind guideline.
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