#include "header.h" // Set up Timer1 in CTC mode to trigger every 20ms // With 16MHz clock and prescaler of 64, and OCR1A = 49999: // 16000000/64/50000 = 20ms period #define T1B_PRESCALE_VALUE 64 void timer_1B_init() { TCCR1A = 0; // 16.11.1 : Normal operation, OC1A/OC1B disconnected TCCR1B = CTC_TOP_OCR1A_IN_TCCR1B; // 16.11.2 : CTC mode top OCR1A TCCR1B |= T1_PRESCALE_SET(T1B_PRESCALE_VALUE); // 16.11.2 : prescaler OCR1A = TIME_MS(20, T1B_PRESCALE_VALUE); // 16.11.5 : Compare match value for register A // OCR1B = ; // 16.11.6 : Compare match value for register B, since not defined, should default to 0 TIMSK1 = (1 << OCIE1B); // 16.11.8 : Enable Timer1 Compare B Match Interrupt // ADCSRA |= (1 << ADSC); // 24.9.2 : start first conversion } ISR(TIMER1_COMPB_vect) { // Empty ISR to ensure proper flag clearing or something like that (p145 : "OCF1B is automatically cleared when the Output Compare Match B Interrupt Vector is executed") }