Video out is amazingly helpful on certain microcontroller projects. Either temporarily in debugging or as an output for users, the ability to see via a monitor is handy. Dave Marples writes on Embedded Rambling how to achieve this on the inexpensive STB32 “BluePill” boards.

One major limitation during the development of an embedded system, especially for programmers who are used to PCs, is the lack of video output. That’s exactly what Vidout provides, using only 24% of the CPU on a STM32F103.

The project objective was simple enough: produce stable video using that board and no (or minimal) additional components.

The tricks are to recreate the video timing, carefully plan your RAM usage, and generate characters rather than raster images when possible.

See how Dave achieved his objective in getting VGA output on a BluePill without sucking up all the microcontrollers resources in this post.