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ch552_hid_cdc
tillitis-key/hw/usb_interface/ch552_fw
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Mikael Ågren f9feb2e74d
Wrap accesses to UART output buffers
2024-09-17 13:36:39 +02:00
..
include WIP: Add USB HID and framing support over UART 2024-07-04 18:45:39 +02:00
.gitignore USB: move firmware for usb-to-serial MCU (CH552) 2024-06-25 15:47:22 +02:00
baud rate calculator.ods USB: move firmware for usb-to-serial MCU (CH552) 2024-06-25 15:47:22 +02:00
encode_usb_strings.py WIP: Add USB HID and framing support over UART 2024-07-04 18:45:39 +02:00
inject_serial_number.py USB: move firmware for usb-to-serial MCU (CH552) 2024-06-25 15:47:22 +02:00
LICENSE USB: move firmware for usb-to-serial MCU (CH552) 2024-06-25 15:47:22 +02:00
main.c Wrap accesses to UART output buffers 2024-09-17 13:36:39 +02:00
Makefile WIP: Add USB HID and framing support over UART 2024-07-04 18:45:39 +02:00
Makefile.include WIP: Add USB HID and framing support over UART 2024-07-04 18:45:39 +02:00
README.md USB: move firmware for usb-to-serial MCU (CH552) 2024-06-25 15:47:22 +02:00

README.md

CH552 USB-to-Serial firmware

Toolchain setup

SDCC:

sudo apt install build-essential sdcc

chprog (for flashing the firmware to a device):

cd ~
sudo apt install libusb-1.0-0-dev
git clone https://github.com/ole00/chprog.git
cd chprog
./build_linux.sh
sudo cp chprog /usr/local/bin

Usage

Build the firmware using a default serial number:

make

Flash the firmware to a device:

make flash_patched

Re-programming the firmware

By design, once the USB to serial firmware is loaded onto the chip, there isn't an intended way to reflash it using only software. However, if 3.3V is applied to the D+ line through a 10K resistor during power-up, then the CH552 will enter bootloader mode, and a new firmware can be programmed onto the chip. Note that the CH552 flash is only guaranteed for a few hundred flash cycles.