When to use CTC mode on compare timer?
Once the process value becomes equal to the set point, a flag in the status register is set and the timer is reset automatically! Thus goes the name – CTC – Clear Timer on Compare! Thus, all we need to do is to take care of the flag, which is much more faster to execute. Let us analyze this CTC Mode in detail with the help of a problem statement.
When to fire an interrupt in CTC mode?
Since there are two CTC channels, we have two different bits OCIE1A and OCIE1B for them. Thus, to summarize, whenever a match occurs (TCNT1 becomes equal to OCR1A = 24999), an interrupt is fired (as OCIE1A is set) and the OCF1A flag is set.
How does CTC on compare work in AVR?
Hence, this comparison takes place in the hardware itself, inside the AVR CPU! Once the process value becomes equal to the set point, a flag in the status register is set and the timer is reset automatically! Thus goes the name – CTC – Clear Timer on Compare! Thus, all we need to do is to take care of the flag, which is much more faster to execute.
When to use an interrupt handler on Arduino?
If the interrupt is enabled, the interrupt handler routine can be used for updating the TOP value. #if 1 // Arduino Datasheet 20.12.2. : The counter value (TCNT1) increases until a compare match occurs with OCR1A, and then TCNT1 is cleared.
How to program timer in CTC mode in AVR?
In clear timer on compare or CTC mode, the OCR0A register is used to manipulate the counter resolution. In CTC mode the counter is cleared to zero when the counter value (TCNT0) matches the OCR0A. The OCR0A defines the top value for the counter, hence also its resolution.
What’s the CTC mode on the ardunino Uno?
Nick Gammon’s cheatsheet for the Ardunino UNO’s ATmega328P (below) shows some hints on the Clear Timer on Compare (CTC) modes of AVR chips. Most of the examples for CTC mode I find use the COMxxx registers of 01 = toggle to control the OCxx pin, which would give a 50% duty cycle at 1/2 the frequency of the timer clearing.