All the output pins are grouped in PORTs: PORTB, PORTC: PORTD. Each port has a corresponding PIN register: PINB, PINC, PIND. If you write a 1 to a bit in the PIN register the output pin will flip:
PIND = 0x10; // Toggle Pin 4 (Port D bit 4)
PIND = 0x10; // Toggle Pin 4 back (Port D bit 4)
This should cause a very short pulse on Pin 4.
Thanks, I will try this today.
What exactly is this code saying? I like to know what I am doing so I can learn from this.