vowstar / ch55x_esp

An USB to Serial bridge based on CH55x series MCU.

Features

A USB to Serial Converter firmware.

It also can automatically detect ESP32 bootloader flow control message, and it will never hurts normal mode (If the host program sets RTS and DTR both high or low, the firmware will force those pins all high).

Issues

Baudrate range: 1200bps - 1.5Mbps

USB endpoints are not configured as ping-pong mode, it makes it even slower. The real performance of this dongle is about 978Kbps, measured by esptool.

This usb to serial converter does not contains any hardware flow control feature and it can only works with 8N1 line coding. I'm working on parity support, but I'm lack of time.

Warning: High baudrate is not accurate at all, 115200 is the last traditional baudrate that it supports. For higher baudrate, please use 250Kbps, 500Kbps, 750Kbps, 1.5Mbps.

Optimizing this code (by rewritten it in assembly) is just like real hell working.

Boards

M5Stack II.

Build

It requires make, sdcc and binutils.

If you got all of them, enter the src directory, and type "make" to generate binary file.

Programming

By WinchipHead's official WCHISPTOOL or LibreCH551 from rgwan.

License

MIT

Authors

Kongou Hikari [email protected]