RE: How is flashing done on custom hardware?

endnode — Sun, 11 Dec 2016 10:16:12 GMT

Hi,

nRF5x chips are equipped with JTAG/SWD interface so as long as you connect these PINs (SWDIO and SWDCLK + obviously VCC and GND - see PIN layout of nRF51422 in chapter 2.2 of Product Specification downloadable from here) to some header or at least test points then you can use any compatible programmer (typically SEGGER J-Link which is also available on nRF5x Dev Kits including option to flash external chips over pin header).

To off-board programming: this is used in case you need to save time on production line or if you don't have space for programming interface on final PCB. Nordic were originally supplying nRF5x chips with SoftDevice pre-loaded but you would anyway need to flash your application code and I guess they stopped offering this part number anyway. Off board programming has specific pit falls like you need specific programming socket + you need good process how to get chip from the reel to the socket and then back (or to new "holder") because that's usually necessary for next step in assembly process = PCB population. Professional manufactures usually offer this service but I assume it is more expensive then programming on final PCB.

I guess you can find several open hardware examples on the internet with nRF51 and nRF52 chips which have JTAG/SWD programming interface on test points/PIN headers (instead of some on-board programming MCU like SEGGER J-Link OB on nRF5x DK boards). You can also see Nordic's nRF51 Beacon Kit example, that's a good one.

Cheers Jan