Looking for ideas to mount coin battery holder to nrf52840-dongle.

[wyattb]

Hi, I ordered the  nrf52840-dongle, but instead of using the USB or external battery to power, I am interested in connecting to a coin battery such as CR2032. I ordered a battery holder, https://www.adafruit.com/product/1870

My question is, do I just wire it directly to the 3v pin or do I need some regulator stuff in between?  Any other solutions? Thanks!

[Dmitry]

You need to make some changes:

The nRF52840 Dongle can also be configured to be supplied from an external regulated 1.8–3.6 V source through the VDD OUT connection point. To enable this, SB2 must be cut and SB1 must be soldered.

CAUTION: Do not have both SB1 and SB2 connected at the same time as this will damage the nRF52840 SoC

[wyattb]

Thank you, that helps.  Is it adaptable from the USB pinouts you think? I am trying to figure out where to solder it. Or possible if there are other alternatives I can use. I m trying to keep this as small form as possible.

Also are there any code changes to sdk files to use the 3v voltages? 

E.g. This table in manual suggests as follows:

snipboard.io/jw4CZk.jpg

[Dmitry]

Didn't you think to use LiPo rechargeable? CR2032 are limited by less than 1mA continuous current, with peaks up to 12mA. And it would look better )

wyattb said:

Also are there any code changes to sdk files to use the 3v voltages? 

No, UICR should be set only for VDDH power.