DAPLink

DAPLink is firmware that runs on a microcontroller that is connected according to a Hardware Interface Circuit (HIC) guideline. This provides methods to program and debug an application running on ARM processors via JTAG or SWD. The interface firmware exposes a USB composite device to the host OS with CDC, HID and MSC endpoints. These endpoints are critical when developing software for microcontrollers. Description of endpoints:

• MSC - drag-n-drop programming flash memory
• CDC - virtual com port for log, trace and terminal emulation
• HID - CMSIS-DAP compliant debug channel
• DFU - USB DFU programming flash memory

For more detailed usability information see the users guide.

WebUSB

This fork/experimental branch adds a USB DFU interface that can be used to flash targets from the browser using WebUSB. The DFU interface can be used standalone with native tools like dfu-util.

This project was done as an experimental proof-of-concept that was a fun exploration, but is no longer necessary because DAPLink incorporates WebUSB support for CMSIS-DAP by multiple means, making it possible to access debug functionality in DAPLink directly from the browser.

Limitations

• This has only been tested on a limited selection of DAPLink hardware:
  • LPC11U35 interface chips, specifically with the Seeed Studio Arch Max board.
  • STM32F103RB interface chips, specifically the embedded STLink/v2-1 on the Nucleo F103RB board
• This has only been tested on Linux and macOS - Windows will almost certainly require fiddling with Zadig to load an appropriate WinUSB/libusb driver for the DFU interface.
• The DFU interface cannot be accessed by Chrome on Windows - Chrome's copy of libusb is missing upstream patches to handle control transfers to composite WinUSB devices more robustly.