Initial flashing of processor

[mosgaard2000]

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]

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

[awneil]

See also: 

devzone.nordicsemi.com/.../178171

Digikey offers programming services:

https://www.digikey.co.uk/en/resources/value-added-services/index

As do Arrow:

https://www.avnet.com/wps/portal/us/solutions/logistics/value-add-and-integration/device-programming-and-modifications/

I couldn't see it on Mouser's site, but it's not uncommon for distributors in general.

3rd party services are also available.

wpaul said:

Include a JTAG/SWD port on your board

The question suggests that this is a new design - so you really should be putting debug & programming access on the board!

You only actually need 2 pins - SWD and SWCLK - although access to RESET also helps.