In last month’s article on making a sound waveform we used the E-blocks SPI bus D/A and memory board to generate a sound waveform of around 400 Hz. In using Flowcode I read that the flowchart is first converted into C and then into assembly code, and that you can embed C into your Flowcode programs to speed the operation up. In this article I describe my attempts to use C to speed up the sound waveform generator. At the same time I discovered how you can use Flowcode to learn C programming.