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64 lines
1.4 KiB
Markdown
64 lines
1.4 KiB
Markdown
# CH552 USB-to-Serial firmware
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## Toolchain setup
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SDCC:
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sudo apt install build-essential sdcc
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chprog (for flashing the firmware to a device):
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cd ~
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sudo apt install libusb-1.0-0-dev
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git clone https://github.com/ole00/chprog.git
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cd chprog
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./build_linux.sh
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sudo cp chprog /usr/local/bin
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## Usage
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Build the firmware using a default serial number:
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make
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Flash the firmware to a device:
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make flash_patched
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## Re-programming the firmware
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By design, once the USB to serial firmware is loaded onto the chip,
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there isn't an intended way to reflash it using only software.
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However, if 3.3V is applied to the D+ line through a 10K resistor
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during power-up, then the CH552 will enter bootloader mode, and a new
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firmware can be programmed onto the chip.
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The Blinkinlabs CH55x Reset Controller can help you do this:
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https://shop-nl.blinkinlabs.com/products/ch55x-reset-controller
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https://github.com/Blinkinlabs/ch55x_programmer
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Note that the CH552 flash is only guaranteed for a few hundred flash
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cycles.
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## License
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Originally based on reference firmware for the CH552 by WCH released
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under the MIT license:
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https://www.wch-ic.com/
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The oldest files Copyright 1999.
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Much changed and added to by Tillitis.
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Check licenses using the reuse tool:
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https://github.com/fsfe/reuse-tool
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Note that so far you need to specify this directory as root, as in:
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```
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$ reuse --root . lint
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```
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