I got the picture but the external device which sent data to P2 8 bits may show High or may show low...

iam looking for some condition which can check which bit is high , now this is done by using CJNE stuff , discussed before. But what if any bit is set and then the external device sents 0 to this.

I have gone through interrupts but what interrupt condition should i use for my case which involves that on 8 bits data should be scanned any bit set controller sent out put to some other external device but as controller is doing this some other bit is set or the same bit goes low...how to make controller work for this..

interrupt is the solution but how to use it here...or which interrupt