SEGGER 9-Pin Cortex-M Adapter
Adapts the 20-pin 0.1″ J-Link/Flasher header to the 9-pin 0.05″ Cortex‑M Samtec FTSH footprint for SWD, JTAG and SWO. Includes 9-pin ribbon cable. [SKU: 8.06.02]
The SEGGER 9-Pin Cortex‑M Adapter enables reliable JTAG, SWD, and SWO connections from any compatible J-Link or Flasher probe to targets that provide the compact 9‑pin 0.05″ Cortex‑M header defined by Arm. It converts the standard 20‑pin 0.1″ ribbon from the probe to the 9‑pin fine‑pitch Samtec FTSH connector used on many modern MCU boards. [SKU: 8.06.02]
Key terms (plain definitions): VTref — target I/O level reference used by the probe to match logic levels; SWD — two‑wire Arm Serial Wire Debug (SWDIO, SWCLK); SWO — Serial Wire Output trace pin; JTAG — 4/5‑wire IEEE 1149.1 debug; nRESET — active‑low target reset line; TRST — optional JTAG reset. [SKU: 8.06.02]
Compatibility
- Works with J-Link BASE/PLUS/ULTRA+/PRO, J-Link WiFi/Compact, and SEGGER Flasher units that expose the 20‑pin 0.1″ connector. [SKU: 8.06.02]
- Targets must provide the 9‑pin Samtec FTSH Cortex‑M pinout; non‑Cortex‑M targets are supported if the same 9‑pin pinout is used. [SKU: 8.06.02]
- TRST is not connected by default; solder bridge NR1 can route TRST to pin 9 when needed for JTAG. [SKU: 8.06.02]
Pinout (9‑pin Cortex‑M header)
| Pin | Signal | Direction | Description |
|---|---|---|---|
| 1 | VTref | Input | Target reference voltage for level matching and power‑present sense. |
| 2 | SWDIO / TMS | I/O / Out | SWD data or JTAG TMS. |
| 3 | GND | Ground | Digital ground. |
| 4 | SWCLK / TCK | Out | SWD clock or JTAG TCK. |
| 5 | GND | Ground | Digital ground. |
| 6 | SWO / TDO | Input | SWO trace (SWD) or JTAG TDO. |
| (7) | Key | — | Key location; physically not populated. |
| 8 | NC / TDI | NC / Out | Not used for SWD; JTAG TDI when applicable. |
| 9 | NC (TRST) | NC | Optional TRST if NR1 solder bridge is closed. |
| 10 | nRESET | I/O | Active‑low target reset. |
Wiring Quick‑Start
- Connect the adapter to the J-Link/Flasher 20‑pin 0.1″ cable with the red stripe at pin 1. [SKU: 8.06.02]
- Attach the included 9‑pin 0.05″ ribbon cable to the adapter and the target’s 9‑pin header, observing pin‑1 polarity. [SKU: 8.06.02]
- Ensure VTref (pin 1) matches target I/O voltage; do not series‑resist this pin. [SKU: 8.06.02]
- For SWD, only VTref, SWDIO, SWCLK, GND, nRESET, and optional SWO are required; leave TDI/TRST unconnected. [SKU: 8.06.02]
- For full JTAG, close NR1 if TRST is required by the target to guarantee TAP reset. [SKU: 8.06.02]
Ready‑to‑run examples
J-Link Commander sanity check
OpenOCD minimal config (J-Link + SWD)
Mechanical
- Probe side: 20‑pin 0.1″ boxed header; target side: 9‑pin 0.05″ Samtec FTSH mating. [SKU: 8.06.02]
- Includes 9‑pin cable; compact PCB fits tight target areas. [SKU: 8.06.02]
Competitor/alternatives map
- SEGGER 19‑Pin Cortex‑M Adapter for Arm’s 19‑pin 0.05″ headers on some boards. [SKU: 8.06.02]
- STDC14 14‑pin 0.05″ ecosystems (alternative header family) require different adapter types. [SKU: 8.06.02]
- Flying‑wire and Tag‑Connect solutions trade convenience for flexibility and test‑point use. [SKU: 8.06.02]
What makes it unique
- Official SEGGER adapter designed and validated for J-Link/Flasher interoperability, reducing pinout mismatch risks. [SKU: 8.06.02]
- Configurable TRST via NR1 to accommodate strict JTAG reset requirements without rewiring. [SKU: 8.06.02]
- Supplied 9‑pin ribbon ensures correct length/impedance for clean SWD/SWO signalling on fine‑pitch targets. [SKU: 8.06.02]