In proper, high-dollar embedded development environments – and quite a few free and open source ones, as well – you get really cool features like debugging, emulation, and profiling. The Arduino IDE doesn’t feature any of these bells a whistles, so figuring out how much time is spent in one section of code is nigh impossible. [William] came up with a clever solution to this problem, and while it doesn’t tell you exactly how much time is spent on a specific line of code, it’s still a good enough tool to be a great help in optimization.
[William]’s solution is to create a ‘bin’ for arbitrary chunks of code – one for each subroutine or deeply nested loop. When the profiler run, you end up with a histogram of how much time is spent per block of code. This is done with an interrupt that runs at about 1 kHz, with macros sprinkled around the code. Each time the interrupt ticks, the macro runs and increases a counter by one. Let the sketch run for a minute or so, and you get an idea of how much time is spent in a specific area of code.
It’s a bit of a kludge, but when you’re dealing with extremely minimal tools, any sort of help in debugging is sorely needed and greatly appreciated.
hile Arduino and its libraries are the quickest way to interface with a sensor and blink an LED, sometimes you shouldn’t have to write and compile code to do something exceptionally simple. [Oliver] realized most of the overly simple functions of a microcontroller could be done from a command line running on that microcontroller and 
