Measuring current on nrf 52840 for the beacon example in the SDK

[Gaurav14]

Hi,

I'm in the debugging stage for the beacon example on the nrf 52840. I have been assigned a task to measure the current on the SDK when the beacon is transmitting. I'm having difficulties in doing so. Can someone here tell me step by step how can I achieve that?
This is what I tried -

1- I cut SB40

2 - Provided power supply of 3.3 V on P21.

When I connect my multi meter on P22, my beacon stops transmitting and I can't read any current on the multi-meter. I'm not sure if I'm doing this all right and that's why if someone can help me out, that'd be great.

[Simonr]

Hi

We generally recommend getting a Power Profiler Kit or a Power Analyzer to measure current on nRF51/52 boards, as a multimeter never will be very accurate.

First off, is the DK running even though you have cut solder bridge SB40 when nothing but the power supply is connected? That should not be the case, please check that the solder bridge is cut properly. Please check that your multimeter is in the Ampere measuring position when measuring. When using a multimeter/ampere-meter to measure current, it is always recommended that you use a true RMS ampere-meter. 

What you're describing should be working if everything is set up correctly. Please check the Development Kit user guide for detailed instructions on how to measure current correctly.

Best regards,

Simon

[Gaurav14]

Hi. Thanks for your reply.
But my main question is, my LED1 doesn't transmit (doesn't blink) after i remove the jumper from P22. When I put the jumper back on P22, it starts to transmit(blink). But if I put the jumper on P22, how can i connect my Multi-meter there?

Or

Is it the case that the LED1 shoudn't blink when I remove the jumper, and I should be able to measure the current by connecting my Multi-Meter to P22?

[Simonr]

Hi

Your second statement is correct. The board won't work when you remove the jumper. In your case, the multimeter would be the "jumper" so you can see the current going through it.

Best regards,

Simon