# Optimization level, can be [0, 1, 2, 3, s]. \r
# 0 = turn off optimization. s = optimize for size.\r
# (Note: 3 is not always the best optimization level. See avr-libc FAQ.)\r
# Optimization level, can be [0, 1, 2, 3, s]. \r
# 0 = turn off optimization. s = optimize for size.\r
# (Note: 3 is not always the best optimization level. See avr-libc FAQ.)\r