A simple yet full featured CMSIS-DAP debug probe for ARM Cortex processors.

DAP42 is a CMSIS-DAP compatible USB JTAG debug adapter for ARM Cortex-A and Cortex-M processors, based on the STM32F042K6 microcontroller.

This project is inspired by the original DAP42 project. There are some additional features implemented on top of the original project:

• Full JTAG support. This is useful in a daisy-chained JTAG scenario.
• When operating in SWD mode, it supports SWO trace.
• USB MSC support with SPI Flash. This can be used to implement either built in driver disk, or as a production programming tool.
• A button and an active-high control signal, allowing the device being used as a production programming tool.

This firmware is also used on the USB coprocessor on SushiBits One Pro. The SushiBits One variant is more similar to the original DAP42, lacking the USB MSC support, SWO code trace, and the buttons. It is based on STM32F042F6 or STM32F070F6 microcontroller.

The saml11 branch of this repository holds a version of DAP42 targeting the onboard debug probe of SushiBits ATSAML11 Mini Pro. The host interface chip is a STM32F042F6.

This is open source hardware under 3-clause BSD license.