peripheral uart power consumption

[KentOverton]

So,

I've got  a working framework for my project - a battery powered appliance that will occasionally trigger one of two solenoids, timestamping the operation and subsequently reporting them to a bluetooth connected phone.

I developed initially on a nRF52 DK (PCA10040 - nRF52832), putting together a heavily modified peripheral_uart sample with I2C and ADC support.

On the nRF52, when idling (Advertising only at a 2 second interval) I measured current consumption at 8 uA  at the current measurement pins while supplying 3.0V at the External Supply pins..

I ported to a newly received nRF5340 DK with minimal changes (GPIO port assignments moved from gpio 0 to gpio 1).  At the same idle state as the nRF52832 (the main loop is a k_sleep(K_FOREVER); statement), current consumption at P22 with power supplied at P21 at  3.0V from a regulated power supply) at about .37 mA.

I had to compile and load  hci_rpmsg to get bluetooth connectivity - as delivered  the nRF5340DK did not seem to have a network core.

Where do I go from here to get reasonable current consumption?

[KentOverton]

Hi.

I'm  providing power from a regulated power supply at 3.0V through the "External Supply" pins on the DK.

I'm measuring current with a BK Precision Bench DMM on. the NRF Current Measurement pins on the DK (I've cut solder bridge SB40).

In the context of what I'm trying to do, I'm running the simplest possible configuration I can. It's a slimmed down version of peripheral_uart that starts advertising, then does a k_sleep(K_FOREVER).

In fact, it's unrealistic. I want my main loop to idle, waiting for either a GPIO interrupt or a Bluetooth connection. The k_sleep is the only mechanism I could make work on the 52832.

I've attached a zip file of the top of my project (the build directories are empty)peripheral_uart-4-20 - Copy.zip

[Hung Bui]

Depends on the advertising interval you have you may have different power consumption. 

I would suggest to turn off all functionality and only sleep to get to the base sleep current before testing with BLE. Having UART running would also draw current as it keeps the clock running.