What is lowest power consumption template code for nrf52840 dongle

RE: What is lowest power consumption template code for nrf52840 dongle

Simon — Tue, 16 Jul 2019 15:02:38 GMT

Take a look at the nRF52840 Product specification, under 6.35.14.1 USB Electrical Specification.

Best regards,

Simon

RE: What is lowest power consumption template code for nrf52840 dongle

Fabio — Sun, 14 Jul 2019 18:26:39 GMT

I was using the USB to power the device when I got 460uA above. Then I decided to power the dongle through the VOUT bypassing the USB. Same code above got me 18uA. Looks like the USB/UART takes a lot of extra power to run?

RE: What is lowest power consumption template code for nrf52840 dongle

Fabio — Sat, 13 Jul 2019 16:37:05 GMT

I followed the additional articles and disabled Logging, disabled ALL pins and I can't seem to bring the draw to anything less than .046ma. I wonder if this is a dongle board issue and I guess this is the minimum I can get to? Do I have to start snapping hardware components off?

RE: What is lowest power consumption template code for nrf52840 dongle

Fabio — Sat, 13 Jul 2019 15:34:02 GMT

I also would like to explain how I am measuring current in case this is wrong. I am applying a 3v source directly on the USB connectors on the board and measuring the current this way. Does the fact that I am applying 3v instead of 5v on the USB influence anything? My thought process is that I want to use two AAA battery to power the dongle through the USB connector. The dongle works fine since nrf52840 runs on 3v anyway. However, I don't know if this can screw up energy consumption somehow

RE: What is lowest power consumption template code for nrf52840 dongle

Fabio — Sat, 13 Jul 2019 03:53:15 GMT

Based on advice I created this simple code:

int main(void)
{

    while(true){
        __WFE();
    }

}

The measurement got way better than 6ma. It went to 0.46ma. However, this
seems still pretty high. With a 1000mah battery I would get a maximum of 63 days
(2 months) by having the CPU doing nothing. I keep hearing we can make these things
last for 2 years. for this to happen I would need to bring this down to 0.046ma,
that is 10 times less consumption. How is that possible if I am getting much more
with a sleeping CPU?

RE: What is lowest power consumption template code for nrf52840 dongle

Fabio — Wed, 10 Jul 2019 12:43:32 GMT

thank you folks. flying to denver right now. will try as soon as back

RE: What is lowest power consumption template code for nrf52840 dongle

Simon — Wed, 10 Jul 2019 09:33:51 GMT

Hei, Fabio.

Check out the links provided by Carl Richard.

6mA sound quite high, it seems like the CPU is running, without any kind of sleep states.

Could you try to opening a very simple application, like the blinky example, and put the chip to system ON mode in the while(true) loop, as described in this link, and measure the current then.

Best regards,

Simon

RE: What is lowest power consumption template code for nrf52840 dongle

Carl Richard — Wed, 10 Jul 2019 08:11:10 GMT

Hello Fabio!

I couldn't locate any specific examples/templates for low power operation, but there is a lot of good material/info here on DevZone. I recommend you to take a look around. Here are some links to get you started:

- nRF51 low power suggestions | A great thread describing how to minimize power consumption on nRF51, most of this also applies to nRF52.

- Optimizing Power on nRF52 Designs | A good blog post giving good tips and a general overview for power saving on the nRF52.

Furthermore you could take a look at the SDK and the power management API.

Best of luck!

- Carl R.