Timothy Smith <[EMAIL PROTECTED]> wrote: > that example is fine, i understand what's happening ( i think ) but > how would i controll the speed of the led blinking? would i use a > different ISR, such a timer compare?
This example is probably not the best example to learn about timers in general, as it uses the timer in (phase correct) PWM mode. For the classical AVRs (and as the example tries to be as generic as possible, so it does not go beyond the features of a classical AVR), the frequency selection options for timers in PWM mode were rather limited: the IO clock frequency is divided by the prescaler, and then by either 2 * 256, 2 * 512, or 2 * 1024, for 8, 9, and 10-bit PWM respectively. Modern AVRs offer much more options here. First, there's the choice between phase correct and fast PWM, and the fixed 8/9/10 bit TOP value can be replaced by a much more flexible TOP value supplied by ICRx or OCRxA. That gives you a much broader range of base frequencies for a PWM timer, and as the blink frequency in the example is tightly coupled to the PWM base frequency, would allow you to smoothely change the blink frequency. -- cheers, J"org .-.-. --... ...-- -.. . DL8DTL http://www.sax.de/~joerg/ NIC: JW11-RIPE Never trust an operating system you don't have sources for. ;-) _______________________________________________ AVR-GCC-list mailing list AVR-GCC-list@nongnu.org http://lists.nongnu.org/mailman/listinfo/avr-gcc-list