Lab1 programs
lab1-ex1   Flash LED by writing to port registers
lab1-ex2   Flash LED, using helper functions to write to port registers directly
lab1-ex3   Flash LED, using helper functions in module led1.c to write to port registers directly
lab1-ex4   Flash LED, using helper functions in module led1.c to write to port registers using pio abstraction
lab1-ex5   Flash LED, using led device driver

Lab2 programs
lab2-ex1   Implement paced loop by writing to timer/counter1 registers directly
lab2-ex2   Implement paced loop, using helper functions in mypacer.c by writing to timer/counter1 registers directly
lab2-ex3   Implement paced loop using pacer.c
lab2-ex4   Flash LED in LED matrix
lab2-ex5   Output pattern by multiplexing LED matrix

Lab3 programs
lab3-ex1   Reimplement stopwatch program using paced loop.
lab3-ex2   Hello world!
lab3-ex3   Using the navswitch
lab3-ex4   Using the navswitch and IR communications.