Use USB on nRF9160DK while set up for current measurements?

RE: Use USB on nRF9160DK while set up for current measurements?

haakonsh — Fri, 04 Oct 2019 10:39:16 GMT

Yes, by shortening those pins the nRF_VDD is supplied by the DK's voltage ragulator, that's supplied by the debug USB. If these two pins are not connected the nRF9160 will not be powered.

RE: Use USB on nRF9160DK while set up for current measurements?

ERIK — Sat, 21 Sep 2019 23:56:40 GMT

So, please confirm for me. If I set up my DK board to measure current with a 'scope as shown in the spec

https://infocenter.nordicsemi.com/topic/ps_nrf9160/pmu.html#unique_1555866438 (cut SB43)

https://infocenter.nordicsemi.com/topic/ug_nrf91_dk/UG/nrf91_DK/hw_measure_oscilloscope.html (install resistor across R60)

do I need to short the two uppermost pins of P24 before using a USB for debugging, or not?

RE: Use USB on nRF9160DK while set up for current measurements?

haakonsh — Fri, 26 Jul 2019 11:51:08 GMT

[quote user="Erik Seavey"]I assume that the USB in that case will not just be powering the DK but will also be operable for communication for programming, debug, etc.[/quote]

The USB is prioritized because a USB source is usually mains powered or have a large battery, while the regular power supply is usually a small battery. While the USB is powering the nRF91 it can still be used for communication.

RE: Use USB on nRF9160DK while set up for current measurements?

ERIK — Wed, 24 Jul 2019 04:18:29 GMT

I think I have found a partial answer in the spec, in the section on Power Supply.

https://infocenter.nordicsemi.com/topic/ug_nrf91_dk/UG/nrf91_DK/hw_power_supply.html

This states that the circuitry will only use one power source at a time and they are prioritized, with USB the highest and P28 the lowest. I think that means that I can use the USB after modification to measure current with a scope, but that the supply actually used if both USB and P28 are powered will be the USB, so no current measurements should be made while both are connect.

I assume that the USB in that case will not just be powering the DK but will also be operable for communication for programming, debug, etc.

Correct?