OpenLink-V1 CMSIS-DAP Debug Unit

Project home page: https://ravikiranb.com/projects/cmsis-dap-debug/

Build your own simple low cost CMSIS-DAP Debug Unit with USB HID interface to debug any ARM Cortex based microcontroller.

Get Hardware and Firmware Files

$ git clone https://github.com/rkprojects/openlink-v1-cmsis-dap.git

Hardware

• 55x30 mm board size.
• Low cost, Low pin count MCU STM32F070F6P6.
• Micro USB type B connector.
• 10-pin cortex debug connector
• All GPIOs on Headers.

Design Files and Gerber

Schematic and PCB Layout files are in folder openlink-v1-cmsis-dap/hardware/
Gerber files are in folder openlink-v1-cmsis-dap/hardware/gerber/
BOM file is in folder openlink-v1-cmsis-dap/hardware/docs/

Schematic and PCB Layout designed with DipTrace Version 3.3.1.3 (Freeware)

Notes on DRC

Before sending gerber files to fabrication please cross check the design rules with your PCB manufacturer's specifications and rerun DRC.

Current DRC violations waved off:

• J3.1 and J3.5 Drill to SMD pad clearance is set to 12 mil as per my PCB manufacturer's specifications however in manufacturer's review it was waved off.
• Y1.1 and Y1.2: Footprint design of Y1 (crystal) is a hybrid one (through hole pad overlapping SMD pad) with possibility of mounting either SMD or through hole crystal. Preferred part is SMD, however if you wish to use through hole part then while soldering raise the height of crystal such that metal case does not touch SMD pads.

Firmware

Software Requirements

• GCC ARM Toolchain
• Keil MDK for ARM if you wish to validate the debug unit. Lite edition is sufficient for this project. You could also use MDK for STM32F0
• STM32CubeProgrammer to flash firmware in USB DFU mode.
• Tested on OS: Windows 10 Build 14393.

Source Code

Firmware source codes are in folder openlink-v1-cmsis-dap/firmware/

Pre-built binaries are present in the openlink-v1-cmsis-dap/firmware/build/ directory. If you wish to rebuild then you may have to modify the Makefile to correctly point to toolchain binaries and run make.

Flash Firmware

• Close J5.1-2 pins with jumper cap to boot from System memory in USB DFU mode.
• Connect the debug unit with USB cable to PC host.
• Start STM32CubeProgrammer and select USB as bootloader interface option.
  • Click Refresh icon - Device information fields will get updated.
  • Click Connect.
  • Click on Open file tab and select openlink_v1_cmsis_dap.hex file in openlink-v1-cmsis-dap/firmware/build/ directory.
  • Click Download to flash.
  • Post download click Disconnect.
• Open J5.1-2 pins and close J5.2-3 pins with jumper cap to boot from Flash memory.
• Reset the board with Reset switch. There is no need to power cycle the board.
• Board should now get detected as USB HID device, cross check this in Device manager.

Validate Debug Unit

• CMSIS DAP Firmware Validation project is in folder openlink-v1-cmsis-dap/firmware/Validation/MDK5.
• Follow the instructions in the readme.txt file there.
• In the step where CMSIS-DAP debugger needs to be selected, select OpenLink-V1 CMSIS-DAP.
• For specific example with LPC4357 MCU based target board refer to project home page.

Pending Stuff

• JTAG interface of the debug unit is not yet tested as all the Cortex-M boards I have are designed with SWD debug port. However JTAG interface is completely implemented in firmware.
• Current 10-pin debug connector (J4) is of through hole type with 1.27mm pitch. Commonly used connectors are of SMD type compatible with samtec FTSH-105- styles.

License

Copyright 2019 Ravikiran Bukkasagara contact@ravikiranb.com

This project uses multiple licenses:

• 
  Schematic and PCB Layout design files are licensed under a Creative Commons Attribution-ShareAlike 4.0 International License
• CMSIS DAP firmware code is licensed under Apache License, Version 2.0
• STMicroelectronics supplied USB Middleware, HAL, LL drivers and startup source codes are licensed under Ultimate Liberty license SLA0044
• Code to bridge USB and DAP data flow is licensed under Apache License, Version 2.0
• Each source/header file specifies corresponding license/copyright notices.

All firmware source codes and hardware design files in this project are distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.