Programming custom board

RE: Programming custom board

bjorn-spockeli — Mon, 04 Feb 2019 13:09:52 GMT

Hi Brian,

when using a nRF52 DK to program an external board, you need to connect the VTG pin on the P20 Header to a pin that is ~2.8V-3.3V. Otherwise, the J-Link OB will program the nRF52 chip on the DK. In orther words, the VTG pin is only a voltage sensing pin that decides which nRF52 that should be flashed, the onboard one or the external one. If you want to power you external board, then connect VDD on the P20 header to VCC on your external board.

Have not run into any issues with regular Dupont/jumper wires.

Bjørn

RE: Programming custom board

Nguyen Hoan Hoang — Sun, 03 Feb 2019 15:22:39 GMT

If your board is powered with ~2.8V-3.3V, it should work. Other voltage might not. I don't think the DK has level shifter to allow you to flash custom board with different voltage. As a low cost alternative, you can use the IDAP-Link CMSIS-DAP debug JTag. Fully support nRF5x serie including flashing Softdevice & DFU without having to use mergerhex.

RE: Programming custom board

SentinelLighting — Sun, 03 Feb 2019 14:37:23 GMT

This appears to be a problem with my cabling that connects between the SDK and my board. I shortened the wires and did a direct connect (as shown in other Devzone articles) and I can talk to my board. The difference is I was originally trying to be a) "self" powered, I connected my onboard VCC to VTG and did not use the VDD on the SDK. b) I went from the SDK to an "test" PCB then went from the test PCB using the Tag Connect cable harness to go to my target PCB. The wires ohm out as correct, but the SDK doesn't seem to be able to talk thru all the wires/intermediate board to program my target.
Questions:

1) Do you have to be powered by the SDK

2) Are there wiring/distance limitations

Any help would be great!