This is basically a hardware interface for Windows, or Linux, to communicate with the Sharp Pocket Computers, a PC-1403 in my demo, using the serial COM port to send files over to the Sharp, by emulating a tape cassette player with the ST-Nucleo board.
The board code takes care of receiving data from the integrated serial-over-USB interface; transform them adding the bits and bytes (checksums, for example) required by the Sharp format; produce a bit stream, with a circular buffer in between to match the speed of the two ends (the serial port working at 600 baud and tape emulator around 500 baud, neither of them having a "flow control" of any sort); then finally modulate the stream to the two-tones typical cassette digital "sound" of the 80's.
MBed OS source code is found here:
Sharp BASIC program files are sent through a standard 'copy' to serial port, and received using CLOAD or MERGE on the Sharp PC. A demo video is here:
Next steps would be - hopefully - to integrate the Sharp BASIC file tokenizer in the board code, since for the moment we still need PocketTools (https://www.peil-partner.de/ifhe.de/sharp/) to do that before sending. Then, CSAVE handling would be nice to have too, but that's an even longer term project...