Important changes to forums and questions
All forums and questions are now archived. To start a new conversation or read the latest updates go to forums.mbed.com.
8 years, 8 months ago.
Current consumption on NRF51_DK with mbed
Hello, I recently started working with the NRF51 Development Kit and the latest mbed. I'm able to compile and load applications just fine, but am seeing a significantly higher current consumption that I was expecting. Specifically, when running a simple application with bluetooth advertising and waiting for events, I am measuring around 280-290 uA in between advertising intervals. I've copied the code below. Do you know what I'm doing wrong, and/or what the expected current consumption should be? Thanks for the help.
#include "mbed.h"
#include "ble/BLE.h"
int main(void)
{
BLE &ble = BLE::Instance();
ble.init();
ble.gap().setAdvertisingInterval(1000);
ble.gap().startAdvertising();
while (true) {
ble.waitForEvent();
}
}
1 Answer
8 years, 8 months ago.
Kevin,
I assume this is because that the current measurement is also measuring the power of the interface circuit as well as other circuitry LDO etc.
Are you powering via USB, this would certainly cause this, see below
Quote:
When not USB powered, the Interface MCU is in dormant state and will draw an additional current of ~ 20 μA in order to maintain the reset button functionality. This will affect board current consumption, but will not affect the nRF51 current measurements as described in Section 5.7 “Measuring current” on page 18.
Can you follow the steps listed in page 18: http://infocenter.nordicsemi.com/pdf/nRF51_DK_UG_v1.0.pdf
Best Regards,
Andrea, team mbed
Hi Andrea - I'm measuring the 280uA whether battery or USB powered. (More or less, I don't remember if there was a 20uA difference). Also, as a couple other reference points: - The same code running on the NRF52 DK gives me 15uA, which is what I expected to see on NRF51 DK. - When running a regular Nordic SDK example on the NRF51, I also see around 15uA during sleep modes. But I am definitely not seeing this when running with mbed and the example code above. I am wondering if something in mbed is not putting the processor to sleep properly? Thanks again...
posted by 24 Feb 2017