Pity the embedded programmer without any real tools, no single
stepping, no breakpoints, no watch points, no printf() or echo,
sometimes not even a LED to flash. How do you see what the value
just read from, say the ADC, was?
Below is a screen grab from my logic analyser showing the value
0x4321 being serialised out a single spare IO port by the debug_serout_1_IO()
function. Note that it's transmitted LSB first so is reversed.