pseudocode.txt

SET timer A to a prescaled value of system clock
SET timer A to CTC mode
SET output from timer A to toggle at CTC

SET timer B frequency to input from timer A output
SET timer B to CTC mode
SET output from timer B to toggle LED

WHILE(forever){
    CHECK POT
    if (POT changed){
        UPDATE OVERFLOW_SWITCH
    }
}

SOLUTION:
# timer A will be a 16-bit timer (T1)
# timer B will be an 8-bit timer (T0)
# timer A Overflow Counter output for channel A (OC1A) = Port B bit 5, or PINB5
# timer B external input (INT0) = Port D bit 0, or PIND0
# timer B Overflow Counter output for channel A (OC0A) = Port B bit 7, or PINB7

# system clock will run at 0.5MHz
# This should allow for reasonably complex code to run (500,000 instructions per
# second)
# timer A will run with with a pre-scaler of 8. This means 62,500 counts = 1 sec
# at 62,500 counts, timer A will toggle the input to timer B
# timer B will be running at 1 cycle / 2 seconds, or 0.5 HZ
# 0.5 Hz will be the switching frequency.
# heat will be controlled by keeping the element on for a fraction of that
# 0.5Hz
# timer B output will be in PWM mode
# duty cycle will be set by potentiometer


# After debugging, timer B will likely have a pre-scaler set to reduce the
# frequency further.