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J-Link EDU Mini

The J-Link EDU Mini offered by SEGGER is a great entry-level debug probe for people on a budget. The only real limitation is that it is limited to the Cortex series of processors.

Pinout and Connector

SEGGER outlines three popular debug connectors on their [knowledge base])https://kb.segger.com/Debug_Connectors) page. The mini uses the 9-Pin (0.05”) Debug Connector, with the pinout shown in the screenshot below.

If the screenshot is not loading, then if one were to look into the connector (that is, into the pin holes) with the slot oriented to the left, and the ribbon connector oriented to the right, then the pinout is as follows:

                        ______________
 1. VTref          |    |              |_____________________
 2. SWDIO/TMS      |    |  (1)    (2 ) |_____________________
 3. GND            |   _|              |_____________________
 4. SWCLK/TCK      |  |    (3)    (4 ) |_____________________
 5. GND            |  |                |_____________________
 6. SWO/TDO        |  |    (5)    (6 ) |_____________________
 7. KEY/No-Connect |  |                |_____________________
 8. TDI            |  |_   (7)    (8 ) |_____________________
 9. NC             |    |              |_____________________
10. nRESET         |    |  (9)    (10) |_____________________
                   |    |______________|
                                       (^Bottom wire typically red, others grey)

Resources

1. Comparison to Other J-Links
2. SEGGER Knowledge Base - Debug Connectors
3. SEGGER Knowledge Base - J-Link EDU Mini