Minum requirements to flash NRF52840 on custom board

RE: Minum requirements to flash NRF52840 on custom board

enny — Mon, 19 Aug 2019 09:53:41 GMT

Hello Simonr,

you are right. The soldering of the chip was the reason. Yes its a verry tricky one. After some try's we got some working. Thank you for your support.

regards Enny

RE: Minum requirements to flash NRF52840 on custom board

Simonr — Wed, 14 Aug 2019 07:41:08 GMT

From what I can see, this circuit should be programmable. Are you sure the chip has been soldered correctly? The nRF52840 is a tricky one to solder properly. There might also be a problem with your J-Link device. Are you able to program any other devices with it?

Best regards,

Simon

RE: Minum requirements to flash NRF52840 on custom board

enny — Tue, 13 Aug 2019 20:00:41 GMT

Hi Simonr,

I have try a board with the components Turbo J mention. No succes. The picture is a part of my schematic, adapted from Reference Layout 4 Version 1.1. Maybe something are wrong. Pleas check and recommend it. (i know ist not nice and easy to read. But not so mutch space on the sheet :-))

RE: Minum requirements to flash NRF52840 on custom board

enny — Tue, 13 Aug 2019 19:52:38 GMT

It's clear. I'm know that the J-Link can't power the board. The board has 2 AAA Batries for VDD.

The parts are already soldered to one of my prototypes. I'm guess the 32 mHZ crystal is also needed ?

RE: Minum requirements to flash NRF52840 on custom board

Simonr — Tue, 13 Aug 2019 08:21:16 GMT

As Turbo J says, you need decoupling capacitors according to the reference layout, and to power the chip from somewhere else, as the JLink won't power it by itself.

If you're still not able to flash your chip, I would like to have a look at your schematics in order to see that everything is set up properly.

Best regards,

Simon

RE: Minum requirements to flash NRF52840 on custom board

Turbo J — Mon, 12 Aug 2019 19:45:02 GMT

You also need all those capacitors on DECx pins - these buffer internal LDO and DC/DC power regulators.

Note that JLInk is not a power source by default.