RE: How to measure current on the nRF52840 Preview DK?

catsunami — Wed, 09 Jan 2019 17:14:05 GMT

It turns out I had to add the following code before the HFCLK initialization to get the current draw to match the spec:

for (uint8_t i = 0; i <= 8; i++)
{
uint32_t test = NRF_POWER->RAM[i].POWER;
}

I actually started with writing 0xFFFF to the POWER register, but switched to this and it still produced the correct result. It has something to do with the POWER register, because using a different register (I tried the same thing with NRF_P0->IN) didn't work.

However, I don't know why I had to do this. I tried this on Rev B and C chips with the same result. Any ideas?

RE: How to measure current on the nRF52840 Preview DK?

Stian Røed Hafskjold — Wed, 09 Jan 2019 12:10:43 GMT

Yes, 2mA is a bit too low, but your setup should be correct. What happens if you put __WFE(); in the main loop?