DAPLink Hardware and Firmware

Hardware: https://oshwhub.com/xivn1987/daplink
Firmware: https://github.com/XIVN1987/DAPLink/tree/master

Similar issues may also happen on other non-official/custom DAPLink firmware builds.

Symptom

pyocd list may show either an unknown probe or no probe:

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pyocd list

Sometimes only J-Link appears, or no available probes are reported, while the same DAPLink still works in Keil.

Fix Steps

1. Check whether USB device is visible:

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lsusb

If detected correctly, you should see something like XIVN1987 XV-Link CMSIS-DAP.

2. Configure udev rules Reference: https://github.com/pyocd/pyOCD/tree/main/udev

Clone repository:

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git clone https://github.com/pyocd/pyOCD.git

Rules are in:

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cd pyOCD/udev/
ls -l

For this custom probe, add an explicit rule (or append to 50-cmsis-dap.rules):

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# 2e3c:5021 XIVN1987 XV-Link CMSIS-DAP
SUBSYSTEM=="usb", ATTR{idVendor}=="2e3c", ATTR{idProduct}=="5021", MODE:="666"

The vendor/product IDs should match lsusb output.

Copy the updated rule file to /etc/udev/rules.d, then reload:

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sudo udevadm control --reload
sudo udevadm trigger

After that, run:

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pyocd list

You should now see the DAPLink probe listed correctly.