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Feather nRF52840 Express Power Profile
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Feather nRF52840 Express Power Profile

by Max44 on Sun May 29, 2022 1:00 am

Feather nRF52840 Power Profile

I'm posting a power profile for the Feather nRF52840 Express using the Nordic PPK2. I wanted to use the
Feather nRF52840 for a battery operated BLE peripheral. It turns out this works well if you use the Nordic
SDK to program the nRF52840 and include their power management routines.

Background

I'm using the Feather nRF52840 with a SHT40 temperature and humidity sensor on a I2C bus. I've set up a custom BLE service with characteristics for temperature, humidity, and battery voltage using a template from the Nordic SDK 17.1.0. The custom service invokes the Nordic power management routines for system on low power mode. The Feather is initialized with all LEDs disabled. The Nordic code also had logging messages disabled and the UART used for this turned off. Every 30 seconds I read the SHT40 data and update the BLE characteristics. My BLE central (the Nordic nRF52840 Developemnt Kit) is programmed to scan, connect, read the data, and disconnect. When the central disconnects, I delay BLE advertising from the Feather peripheral for 30 seconds.

PPK2 Power Measurement
Feather_SHT40_PPK.png
Feather_SHT40_PPK.png (279.45 KiB) Viewed 45 times


As seen above, there is average current of 110.49 uA in the selected 30 second cycle. This indicates the Nordic power management is working well. Even better, the current during the idle time drops to around 20 uA.

Conclusion

Yes! The Feather nRF52840 Express performs well for battery operation if programmed using the Nordic SDK. While the window displayed above is not the entire picture, battery life is expected to be be good with similar readings in the 30 second cycle.

Max44
 
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Joined: Tue Jul 10, 2018 12:37 pm

Please be positive and constructive with your questions and comments.