ARM-based device have 8-pin 2x4pin JTAG header. J-Link debug probe have standard 20-pin J-Link connector. I have 8-pin 2x4 Socket-Socket IDC Ribbon Cable. enter image description here

One end connects to the 8-pin JTAG header on device, and the other end should be connected to J-Link probe. What is better way to interface this 2x4 pin socket with 20-pin J-Link probe? Should be used a custom-built connector for this, which connects matching pins? Please advice the most handy way.

  • \$\begingroup\$ I just make up little PCBs that convert from 20 pin to 10 pin connecting the relevant pins and it works fine. \$\endgroup\$ – DiBosco Sep 14 '17 at 12:04

enter image description here

This wasn't too hard too find. I am sure there are more.

searched ... 20-pin J-Link connector 8-pin 2x4

This adapter is designed to allow standard 20-pin ARM JTAG devices to connect to the FDI 10-pin mini-JTAG on µEZGUI units and ARM based SOMDIMM units.

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with 100k Pullup to SWDIO and 100k Pulldown to SWCLK

  • \$\begingroup\$ True, but trick is that pinout placement on custom header (8-pin in my case) will not match (and not obliged) the standard 20-pin J-Link connector, as no standards on pin positions, every manufacturer use own pin placement. So without custom converter board this can't be solved. \$\endgroup\$ – minto Sep 14 '17 at 12:42
  • \$\begingroup\$ So make your own board up in that stylee. \$\endgroup\$ – DiBosco Sep 14 '17 at 12:43
  • \$\begingroup\$ Or 20-pin version of this fly wire cable. \$\endgroup\$ – minto Sep 14 '17 at 12:51
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    \$\begingroup\$ Note that in the 20 wire cable, at least every second one is GND. For high-speed JTAG, you need to take crosstalk into account when designing such an adapter. \$\endgroup\$ – Simon Richter Sep 14 '17 at 12:55
  • \$\begingroup\$ I am sure you could mate 10x2 Male header to a Female 4x2 socket and connect with short resistor wire leads but it might look like a centipede mating with a spider. \$\endgroup\$ – Sunnyskyguy EE75 Sep 14 '17 at 12:59

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