Hi. I use ccp and timer1 to capture external signal, the period of the signal is larger than timer1's. So timer1 will timeout during capture. My question is if ccp capture external signal and at the same time timer1 timeout, then both interrupt flag will be set, or the TMR1IF is set earlier or else? I use pic16f877. thx. zhaoyue wang -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist