I have AVR MCU.
I am playing with timer now.
What I need ? I have timer counting up with some frequency. In each interrupt I am incrementing variable, and somewhere I need to check value of this variable and if equals 100, I need to stop timer count, set new value for frequency and continue counting down.
I cannot get how to stop timer and set new value to compare.
I have tried to select no clock source using mux selector register, but it continue to count up.
What is correct way to do this. Here is my code
// Arduino timer CTC interrupt example // www.engblaze.com // avr-libc library includes #include <avr/io.h> #include <avr/interrupt.h> #define LEDPIN_UP 9 #define LEDPIN_DOWN 8 int current_value = 0; void setup() { Serial.begin(9600); // pinMode(LEDPIN_UP, OUTPUT); // initialize Timer1 cli(); // disable global interrupts TCCR1A = 0; // set entire TCCR1A register to 0 TCCR1B = 0; // same for TCCR1B // set compare match register to desired timer count: // OCR1A = 3123; OCR1A = 1562; // turn on CTC mode: TCCR1B |= (1 << WGM12); // Set CS10 and CS12 bits for 1024 prescaler: TCCR1B |= (1 << CS10); TCCR1B |= (1 << CS12); // enable timer compare interrupt: TIMSK1 |= (1 << OCIE1A); // enable global interrupts: sei(); } void loop() { //digitalWrite(LEDPIN_UP, current_value); Serial.println(current_value); if(current_value==255) { TCCR1B |= (0 << CS10); TCCR1B |= (0 << CS12); Serial.println("Reseting timer"); } } ISR(TIMER1_COMPA_vect) { current_value++; } 
