I have just entered into AVR MCU programming using gcc-avr, but when I see sample programs I am not able to make out much from the code:
DDRD |= (1 << PD7); TCCR2 = (1 << WGM21) | (0 << WGM20); TCCR2 |= (1 << COM20); TCCR2 |= (6 << CS20);
I do not see also any declarations variables : DDRD, PD7, TCCR2, WGM21, WGM20, COM20, CS20, but they are directly used. Please let me know how I can know all pre-defined variables and its usage? It becomes very difficult in understanding the code without knowing the same.
Thanks in advance.