NRF52832 pins toggling during FW Flash

[Christopher]

I am working on a product which uses the nRF52832-CIAA. Whenever I update the firmware via JLINK/SWD, there is a pin (P0.19) which toggles during the FWUP process.

This signal only drives an NFET and has a pulldown on it, so it is not floating. I see it being actively driven from the MCU, and it is causing device failures during FW UP.

Here is an image of P0.19 during FW flashing via SWD.

Any advice? Is this expected?

Thanks!

[Simonr]

Hi

The pin likely keeps toggling because the erase won't "take effect" until you reset the chip. If you try to erase the device, and then resetting it before terminating the JLINK session, you should see the P0.19 stop toggling. As to what exactly causes it to toggle, the firmware you are using were most likely at one point telling the P0.19 to toggle. You will just have to go through your code to find out what exactly is causing it. 

Best regards,

Simon