here is my code: volatile uint8_t first_edge = 'A'; ................................. ISR(TIMER1_OVF_vect) { if(first_edge <= 'Z') { avr2pc(first_edge); //avr2pc to transmit character to PC ++first_edge; }else { first_edge = 'A'; }
} my result: I only show 'A' in hyperterminal : => first_edge can't update values; Please tell me why? _______________________________________________ AVR-libc-dev mailing list AVR-libc-dev@nongnu.org http://lists.nongnu.org/mailman/listinfo/avr-libc-dev