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timerembeddedinterruptinterrupt-handling

Embedded system interrupts

I have been reading about interrupts in embedded systems and I came across this.

In Normal Mode, the timer triggers interrupt handlers. These can do practically any function you want, but they run on the CPU, which prevents anything else from running at the same time. In CTC mode, you can also trigger interrupts, but it is also possible to not use interrupts and still toggle an output pin. Using it this way, the functionality occurs parallel to the CPU and doesn't interrupt anything. So I have the following doubts:

  • What does it mean by toggling the output pin in CTC mode? Does it mean that the processes are running in parallel? That would imply that both the main loop and interrupt function are running in parallel? I am not sure about this.
  • Is it safe to assume that a timer counts more in CTC mode as it is resetting the timer register each time it matches with the compare register?
Solution

  • The hardware circuitry that constitutes the timer peripheral within the microcontroller is able to perform a comparison and toggle an output in CTC mode. This logic is performed in hardware, without relying on the CPU to execute software instructions. Therefore, the CTC mode compare and toggle occurs in parallel with whatever the CPU happens to be executing.

    I don't understand what you mean by the timer "counts more". More as in more often or faster rate? More as in greater total counts? Regardless, I think the answer is no. The timer counts at the rate of the input clock that is driving it. In CTC mode the timer counts up to the comparison value that you have configured it for.