f0c6016a6e
Terminate all 64-byte frames with a zero-length packet. Handle incoming zero-byte frames by ignoring them. This fix addresses issues related to transfers of an exact length of 64 bytes (or multiples thereof) on all platforms. For simplicity, all 64-byte frames are terminated, regardless of whether they are the last or not. |
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| .. | ||
| inc | ||
| LICENSES | ||
| src | ||
| .gitignore | ||
| encode_usb_strings.py | ||
| inject_serial_number.py | ||
| Makefile | ||
| README.md | ||
| REUSE.toml | ||
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.
License
Originally based on reference firmware for the CH552 by WCH released under the MIT license:
The oldest files Copyright 1999.
Much changed and added to by Tillitis.
Check licenses using the reuse tool:
https://github.com/fsfe/reuse-tool
Note that so far you need to specify this directory as root, as in:
$ reuse --root . lint