nrf52840 SPI huge current draw

[davidz]

I am using nrf52840 DK (pca10056) board and nrf5SDK 16. There is one low power sensor connected to the board via SPI interface. My program consume less than 30uA before I turn on the SPI. After turning on the spi and take data, the current draw increases to around 2mA. After using the SPI bus to acquire data from the sensor, I use nrf_drv_spi_uninit() command to turn off the SPI. The current draw remains around 2mA, which is huge. I am using SPI0. I followed the guide here (https://devzone.nordicsemi.com/f/nordic-q-a/48918/spi-power-consumption-does-not-go-down-after-uninit) and added the following commands: 

*(volatile uint32_t *)0x40003FFC = 0;
*(volatile uint32_t *)0x40003FFC;
*(volatile uint32_t *)0x40003FFC = 1;

There is no effect at all. 

Then I tried SPI1 and SPI2 bus, the result is the same. Is there a way to turn off the spi after data acquisition? Thanks in advance.

[davidz]

I found out the reason. The sensor that I am using has always been connected in high current mode in previous design, which caused this issue. After fixing the sensor connection, the current drain dropped to 70uA when SPI is idle. Also, nrf_drv_spi_uninit() works. 

[Karl Ylvisaker]

Hi,

I am glad to hear that you were able to resolve your issue!

Do not hesitate to open a new ticket in the future if you should encounter any other issues or questions.

Good luck with your development!

Best regards,
Karl