Hi,
I am planning to design a device based on nRF51-dk but with external programmer. I have ST-Link available so I thought I just provide a simple walk through showing how to set it up.
Firstly, here is shown how to wire up the programmer with dk. I used only four wires so only one ground pin. On the devkit P18 connector these are the pins 1,2,3,4.
Next set the debug interface and go to settings.
Select SW port instead of JTAG and if your device is powered and wired up correctly you should see the SW Device in the window on right.
Almost there! Just add the flash device by selecting the Flash Download tab and clicking on Add.
That is it and it works for me. You can get the the programmer for about £10.
Hope this helps
Milan