Thanks to V-USB, software-based USB is all the rage now, with a lot of uses for very small and low power microcontrollers.[ZiB] wondered if it would be possible to implement a USB controller on the STM8 microcontroller (Google translation) in software and succeeded.
The STM8 is a bit of a change from the usual 8-bit micros we see like AVRs and PICs. [ZiB] chose the STM8S103F3, although any chip in the STM8 family will work with this project when a 12MHz crystal is attached.
The build began by generating USB signals with the help of a whole lot of NOPs. This code doesn’t take up much space – only 300 bytes, and the receiving code (Google translation) is similarly sized.
The code isn’t quite there yet, but [ZiB] has proven a software-based USB implementation on the STM8 is possible. All the code is available for download (comments in Russian) and a video demoing the project available below. If anyone cares to translate this project to English, we’ll post a link to your work here.
