Simulate & Log AVR

Below are steps to run AVR program on AtmelStudio simulator and log register values.

1. Debug > Start Debugging and Break
2. Debug > Set Stimulifile > Select test.stim (see below)
3. Debug > Execute Stimulifile
4. Debug > Continue

main.cpp

#include <avr/io.h>       // For DDRB, PORTB, PORTB5.
#include <avr/sfr_defs.h> // For _BV().

int main(void)
{
	// Set pin PB5 as output.
	DDRB |= _BV(DDB5);
	
	while (true)
	{
		// Drive pin PB5 high.
		PORTB |= _BV(PORTB5);
		
		// Drive pin PB5 low.
		PORTB &= ~(_BV(PORTB5));
	}
}

test.stimuli

// Log DDRB and PORTB registers
$log DDRB
$log PORTB

// Save result in "output.sim"
$startlog output.stim

// Log for 20 clock cycles
#20

$stoplog
$break

Output

Results are appended to the end of existing file. If register values do not change, nothing will be added to the file. Only changes are recorded.

output.stim

#1
DDRB = 0x20
#1
PORTB = 0x20
#2
PORTB = 0x00
#4
PORTB = 0x20
#2
PORTB = 0x00
#4
PORTB = 0x20
#2
PORTB = 0x00

After 1 cycle, DDRB changed to 0x20.

Then, after another 1 cycle, PORTB changed to 0x20.

2 cycles afterwards, PORTB changed to 0x00.

... and so on.