Programming an external board using NRF52dk

[connorshannon]

Hello,

I'm trying to upload code to an external board using an NRF52dk, and am having an error in vscode as shown below.

My issue seems to be very similar to the one being discussed here  Programing custom PCB Board through nRF52-DK 

However, the comments on this post say that there is a connection issue, but I've double checked the connections I'm using and they all look fine. I'll attach a photo of these connections, in case there is something I am overlooking.

Other possibly relevant information is that I'm using vscode to build the code located in the peripheral_uart sample, which I've already tested on one board and works fine. Other than that, all I am doing is flashing the code to the original board (not the external one that I'm trying to program through the original), and it is at that point that I get the error shown above. 

Any help or advice would be greatly appreciated, thank you!

[Vidar Berg]

Hello,

The P19 and P20 headers are only for programming external targets. The SWD lines routed to these headers are not connected to the onboard nRF52832 chip. If you want to program a DK with an external debug probe or another DK, you should use the Debug In port instead. Note that this requires a 9-pin Jlink cortex M cable. 

- Debug out for programming external boards

- Debug input

Best regards,

Vidar

[connorshannon]

I'm not sure I understand what you mean. To give more information, I am currently testing the ability of the board to program an external board by using an extra NRF52dk. However, eventually I will be using the board to program a custom circuit board.

[Vidar Berg]

You can use the debug out headers (P19 or P20) to program external boards, but you cannot use these headers as a debug input to program the onboard nRF52832 chip. From the picture, it appears you have connected the SWDIO and SWDCLK from P20 on the first kit to the same pins on the second kit. This will not work, as these pins are not connected to the nRF52832 chip you are trying to target on the second board. 

[connorshannon]

I tried to follow the circuit connections schematic in the other thread that I attached, in which someone was doing something similar and seemed to have success. Are you saying that following those steps is not the right way to do this? If so, what should I be doing instead?

[Vidar Berg]

The connections from DK #1 which you are using as a programmer appear to be correct based on the picture. However, you cannot connect these SWD lines to the same pins on the second board, as the pins on the Debug Out headers are only connected to the J-Link programmer. To program the nRF52832 on the second board with an external debugger or another DK, you need to use the Debug In port. I looked at the other thread you linked, but it doesn’t seem like they were able to make it work either.

[connorshannon]

I see, so the only way to program something through my programmer board is to use the debug in port on whatever the external board is? I was under the impression that external boards without the debug in port requiring the special cable could still be programmed.

[Vidar Berg]

Debug out ports can be found on development kits with an onboard debugger. Custom boards will usually have only a debug in port. How the SWDIO and SWDCLK lines connected to the target chip are exposed is entirely up to the board designer. The 9-pin connector like the one used on the 52 DK is quite common, but you are free to use any other connector or header if you are designing your own board.