Segger Debug Out on DK can't see my target

[Bret Foreman]

I just got a new target board back from fab/assembly and I'm trying to use the debug out connector on the PCA10028 to program the new target.

My target is the NRF51822-CFAC-R

I've wired J19 on the DK as follows:

Pin 1 - tied to the same 3V supply that powers the DK and my target
Pin 2 - SWDIO (pin H2) on my target
Pin 3 - GND on my target
Pin 4 - SWDCLK (pin C8) on my target

In nRFgo Studio, I'm able to see the Segger on the DK but the Segger is not able to see my target device. Is there any additional setup I need to do on the DK in order to download to my device?

[Bret Foreman]

It always turns out to be the simplest thing. I'm connecting to my target using pogo pins to landing pads. The whole works is pretty small and my fixture seemed precise. It turns out that the board was shifting in the fixture and the pogos were not lining up reliably.

I've now got the board programmed with an S110 SD and with my test app. And it's connecting to my phone.

One pro-tip: It's very easy to accidentally program the DK rather than the target if you forget to power up the target. You really can't tell which is being programmed. So I loaded the "blinky" app onto the DK. If the LEDs are blinking, I know I programmed my target, not the DK.

[Jay Tyzzer]

If you use nRFGo studio you will see the part number and Build Code for the device you are programming. The part on the nRF51-DK is a nRF51422. If you are using a nRF51822 you should see that listed instead of the one on the DK.