Number of clock cycles per instruction Posted on March 07, 2016 at 11:18Good morning to everyone.I am trying to figure out how to toggle periodically a digital output pin with a given frequency. The system clock is configure the internal oscillator, so it should be 16 MHz.I set a timer with a prescaler of 101, so, if I understand correctly, it should count 1 every 100 cock tick.Now, for example, I am trying to toggle a pin evry 20 ms. If I understand correctly, 16 MHz, should be 16000000 clock cycles per second. If I count 1 every 100, the timer should be 160000 every second. 20 ms is 1/50 seconds, so 1600000/50 = 3200.In my code, I execute various type of operation in an infinite cycle. When I have to evaluate if 20 ms are passed, I verify the STM counter. If 3200 counts are passed from before, I change the output.The control implemented is something like this: ULONG ulNow = STM.CNT.R; ulElapsedTime = ulNow - ulWaveTimer; if (ulElapsedTime >= 3200) /* Time passed. Change output and reset timers. */The fact i
