Initial flashing of processor

Question

Hi, 
 What are the possibilities for flashing a new nRF52840 device on a custom board. Do I need the jtag interface or does the device comes preloaded with some wireless bootloader?

wpaul · Accepted Answer

If you buy brand new chips from a distributor (Mouser, DigiKey, etc...) they will be completely blank. The UICR will be blank too. (This means the reset pin configuration won't be set, and you'll have to configure that too, based on your design.) You have a couple of options: 
 1) Buy an off-board programmer with a socket that matches the nRF52840 and flash each chip before assembling your boards 
 2) Pay a company to do that for you (they might be able to put them back on a reel after programming too) 
 3) Include a JTAG/SWD port on your board and flash your boards once assembly is complete 
 Note: sometimes people just leave some bare copper pads on the board rather than mount a 10-pin SWD header. The idea is that you make a custom jig with pins that match up with the pad layout and just press the board against the jig long enough to program it. 
 -Bill

Initial flashing of processor

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