Hello Engineers: I have question to ask about portb of 17c44. Right now, I have a PIC that does the counting up/down of encoder of a motor. The 'A' and 'B' of encoder is connected to RB0 and RB1 respectively. This PIC works perfectly well when it is tested alone. I have another PIC , the controller, that needs the reading of the position of the motor. To do that, I am sending a high pulse from RE2 to RA1 of the above PIC. Upon interrupt, instead of giving me the reading of the position, the up/down counter PIC crashed! After rectifying the problem, I found that whenever there is a interrupt, the input of 'A' and 'B' would drop from 5V to 3V periodically. This only happens when there is a interrupt. Does anyone knows what happened? As this is my final year project, I need the answer urgently. If there's anyone who knows the answer, I will be very grateful when you reply my mail promptly. A million thanks in advance. With regards, Mr T. S. Koh