Reason for pinout on nRFDongle Pin Header vs. Tag Connect

[parksj10]

Hi,

I was wondering if you could shed some light on why the pin assignments on the nRF dongle Tag Connect port aren't the same for the 1.27 mm SWD header? I can tell that nRF is following ARM Cortex standard for the SWD port, are you following a a standard for the Tag Connect?

[Håkon Alseth]

Hi,

 

There are more gnd pins on the 10 pin swd header, as compared to the tag-connect TC2050-IDC.

Here's a recommendation on the pin out for both SWD and JTAG communication:

https://shop.collion.de/out/media/TC2050-ARM2010.pdf

 

Kind regards,

Håkon

[parksj10]

Håkon Alseth , thanks for the response! I understand the number of pins is higher for JTAG than SWD, but it seems that the TC and 10 pin header are both operating under SWD, however it looks like VBUS only exists on TC, whereas reset only RESET only exists on 10 pin... I'm a little unclear on why these differences exists? Are they not both intended to work with e.g. jlink?

[Håkon Alseth]

The only pins that you strictly need for programming is SWDIO + SWDCLK and GND. A RESET command can be sent over SWD. 

Kind regards,

Håkon

[parksj10]

 Håkon Alseth just got back to the board design , did you happen to know why VBUS only exists on the TC, whereas the pin header has pin 5 to ground? 

[Håkon Alseth]

Some debuggers are able to supply voltage to the DUT. This is why the VBUS is recommended routed out when using the TC layout.

 

Kind regards,

Håkon