# picoDAP The CH552E-based picoDAP is a CMSIS-DAP compliant debugging probe with SWD protocol support. It can be used to program Microchip SAM and other ARM-based microcontrollers. The Firmware is based on [Ralph Doncaster's](https://github.com/nerdralph/ch554_sdcc/tree/master/examples/CMSIS_DAP) DAPLink-implementation for CH55x microcontrollers and Deqing Sun's [CH55xduino](https://github.com/DeqingSun/ch55xduino) port.  # CMSIS-DAP CMSIS-DAP provides a standardized way to access the Coresight Debug Access Port (DAP) of an ARM Cortex microcontroller via USB. CMSIS-DAP is generally implemented as an on-board interface chip, providing direct USB connection from a development board to a debugger running on a host computer on one side, and over JTAG (Joint Test Action Group) or SWD (Serial Wire Debug) to the target device to access the Coresight DAP on the other. As a USB HID compliant device, it typically does not require any drivers for the operating system. For more information refer to the [CMSIS-DAP Handbook](https://os.mbed.com/handbook/CMSIS-DAP).  # Compiling and Installing Firmware ## Installing Toolchain for CH55x Install the [CH55x Software Development Kit for the SDCC compiler](https://github.com/Blinkinlabs/ch554_sdcc). Follow the instructions on the website. In order for the programming tool to work, Python3 must be installed on your system. Most Linux distributions already include this. Windows users can follow these [instructions](https://www.pythontutorial.net/getting-started/install-python/). In addition pyusb must be installed. On Linux this can be done by running the following commands: ``` sudo apt install python3-pip sudo pip install pyusb ``` ## Installing Drivers for the CH55x Bootloader ### Linux You do not need to install a driver. However, by default Linux will not expose enough permission to upload your code with the USB bootloader. In order to fix this, open a terminal and run the following commands: ``` echo 'SUBSYSTEM=="usb", ATTR{idVendor}=="4348", ATTR{idProduct}=="55e0", MODE="666"' | sudo tee /etc/udev/rules.d/99-ch55x.rules sudo service udev restart ``` ### Windows On Windows you will need the Zadig tool (https://zadig.akeo.ie/) to install the correct driver. Click "Options" and "List All Devices" to select the USB module, then install the libusb-win32 driver. ## Entering CH55x Bootloader Mode A brand new chip starts automatically in bootloader mode as soon as it is connected to the PC via USB. Once firmware has been uploaded, the bootloader must be started manually for new uploads. To do this, the board must first be disconnected from the USB port and all voltage sources. Now press the BOOT button and keep it pressed while reconnecting the board to the USB port of your PC. The chip now starts again in bootloader mode, the BOOT button can be released and new firmware can be uploaded within the next couple of seconds. ## Compiling and Uploading Firmware Open a terminal and navigate to the folder with the makefile. Run ```make flash``` to compile and upload the firmware. If you don't want to compile the firmware yourself, you can also upload the precompiled binary. To do this, just run ```python3 ./tools/chprog.py picodap.bin```. # Operating Instructions Connect the picoDAP to the target board via the 10-pin connector or the pin header (RST / DIO / CLK / GND). Make sure the target board is powered. You can supply power via the 3V3 pin (max 150 mA) or the 5V pin (max 400 mA). Plug the SWD Programmer Stick into a USB port on your PC. Since it is recognized as a Human Interface Device (HID), no driver installation is required. The SWD Programmer Stick should work with any debugging software that supports CMSIS-DAP (e.g. [OpenOCD](http://openocd.org/)). Of course, it also works with the [SAMD DevBoards](https://github.com/wagiminator/SAMD-Development-Boards) in the Arduino IDE (Tools -> Programmer -> Generic CMSIS-DAP). # References, Links and Notes 1. [Project Files \(Github\)](https://github.com/wagiminator/CH552-picoDAP) 2. [DAPLink](https://github.com/ARMmbed/DAPLink) 3. [CH55xduino](https://github.com/DeqingSun/ch55xduino) 4. [Ralph Doncaster's Implementation](https://github.com/nerdralph/ch554_sdcc/tree/master/examples/CMSIS_DAP) 5. [CMSIS-DAP Handbook](https://os.mbed.com/handbook/CMSIS-DAP) 6. [SDCC Compiler](https://sdcc.sourceforge.net/) 7. [CH55x SDK for SDCC](https://github.com/Blinkinlabs/ch554_sdcc) 8. [OpenOCD](http://openocd.org/) 9. [SAMD DevBoards](https://github.com/wagiminator/SAMD-Development-Boards)  # License  This work is licensed under Creative Commons Attribution-ShareAlike 3.0 Unported License. (http://creativecommons.org/licenses/by-sa/3.0/)