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8d8f4c7faf
- Merge Makefile and Makefile.include into Makefile - Format structure - Remove unused variables, targets etc. - Add missing check if it is ok to send data to the FPGA. - Remove 'baud rate calculator.ods' - Update encode_usb_strings.py to generate strings for CdcCtrlInterfaceDesc, CdcDataInterfaceDesc, FidoHidInterfaceDesc, TkeyCtrlInterfaceDesc. Also store generated strings in UTF-16 instead of hex. - Update usb_strings.h to match new encode_usb_strings.py output. - Remove unused struct SetupReqBuf.
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.
The Blinkinlabs CH55x Reset Controller can help you do this:
https://shop-nl.blinkinlabs.com/products/ch55x-reset-controller
https://github.com/Blinkinlabs/ch55x_programmer
Note that the CH552 flash is only guaranteed for a few hundred flash cycles.