How to use P21 external supply in nRF52833 DK

[Ziyao Zhou]

Hi,

I am using nRF52833 DK and power it using P21 External supply. I connected P21 with the power profiler 2 and give 1.8V.  It works for serveral days, however, today I notice when I give 1.8V the program will not run. If I change to around 2.2V, it start running.

I have three questions:

1. What happen to the DK, before it can work under 1.8V, now it cannot.

2. When I am measure the current through P21, with all default setting(VDD power source, vEXT-nRF off, default), am I measuring the total current consume by the nrf52833 and interface MCU?

3.Can P21 use together with Lipo battery, if I connect a battery here, is there any battery management circuit after P21.

I have found some schemetic but I have no clue about what is happening in this DK. Thank you so much for your time!

[Simonr]

Hi

1. To power the nRF52833 from P21, you should slide the switch SW10 to the ON position and SW9 to the middle position (VDD).

2. This will only power the nRF52833 SoC, but please note that this is not the recommended way to measure current consumption. See section 5 of the DK user guide for information on how to do that. https://docs.nordicsemi.com/bundle/ug_nrf52833_dk/page/UG/dk/intro.html 

3. There is a separate connector for Li-Poly batteries on the nRF52833. This is the J6 or P27 that is designed for a Li-Poly battery source at 2.5-5V. If you're using it the SW9 pin should be set to the leftmost position (Li-Po).

Best regards,

Simon

[Ziyao Zhou]

Hi, thank you for your reply!

Simonr said:

1. To power the nRF52833 from P21, you should slide the switch SW10 to the ON position and SW9 to the middle position (VDD).

I notice when I switch SW9 tp ON, my code will not run, only when I put the thing default, my code will run.

Simonr said:

2. This will only power the nRF52833 SoC, but please note that this is not the recommended way to measure current consumption. See section 5 of the DK user guide for information on how to do that. https://docs.nordicsemi.com/bundle/ug_nrf52833_dk/page/UG/dk/intro.html 

What is the problem if I use the default setting (VDD power source, vEXT-nRF off) setting to power, will I have some noise or what.

Simonr said:

3. There is a separate connector for Li-Poly batteries on the nRF52833. This is the J6 or P27 that is designed for a Li-Poly battery source at 2.5-5V. If you're using it the SW9 pin should be set to the leftmost position (Li-Po).

I have accidently connect one battery in P21 and it works stably for a long peroiod. I want to know whether it will damage the DK if I keep using it

[Simonr]

Hi

1. Switching SW9 will only power the nRF52833, so I think your code still runs, but the interface MCU and thus logging will no longer be printed onto the computer, nor will any LEDs blink, if that's how you determine if the application is running or not. I.E. the radio should still run with SW9 set to ON.

2. Yes, this will power more than just the nRF52833, and you will see inaccurate current consumption numbers as it also powers the LEDs, etc. of th eDK. P22 will only power the nRF52833 DK, while you can plug in a USB cable to J3 to power the rest of the DK and get accurate current consumption numbers while I.E. doing logging.

3. You should follow the DK user guide, as we can't provide any guarantees if you don't. Powering P21 with a battery most likely will work and not damage the DK, but we can't guarantee that it won't as this is not something we've done extensive testing on on our end.

Best regards,

Simon

[Ziyao Zhou]

Hi

Thank you for your reply! I am using BLE and when I switch SW9 to ON I will notice it stop working. Only when I swithch off it works, it is really strange.

[Simonr]

Hi

Do you mean SW10 VEXT->nRF or SW9 (Li-Po, VDD, USB). Switching SW10 should not affect the nRF as long as you have powered the device from an external supply. SW9 switches which power source is used. Between Li-Po, VDD and USB.

Best regards,

Simon