3.1.1 Initialization
To generate an output from the PWM the Output Compare Pin of Timer1
(OC1A) is set up as output.
- The clock source for the timer is prepared by starting the PLL and locked to the system clock (required).
- The PLL takes approximately 100ms to lock onto the system clock and it is therefore necessary to wait for the PLL lock flag before proceeding.
- When the PLL is locked it is selected as clock source for the timer.
- The PWM mode is selected so that the OC1A pin toggles on compare match.
- Top value of the timer is set to 0xFF. The Top value affects the resolution and the base frequency of the PWM – the higher the Top value is the higher resolution and the lower base frequency.
- The prescaler is set, which also starts the timer.
- The Overflow interrupt is enabled.