SPI slave mode power usage

[daan]

Hi,

when using the spi peripheral in slave configuration, what can I expect at power consumption level? 
does the spi peripheral derive its clock from an internal system clock (meaning zephyr will probably not enter its lowest power mode since there is a pending clock dependency) or from the sclk line ?

thanks ! 

[ovrebekk]

Hi 

Are you thinking about the current consumption while the SPI slave is in the middle of a transaction, or the current consumption when nothing is being sent and chip select is high?

When the SPI slave is active it will use the internal high frequency clock, and current consumption will be relatively high. 

When the bus is idle the interface will not request the clock, and the current consumption in sleep will be similar to I_ON_RAMON_GPIOTE, which is documented for the nRF52840 here.

Best regards
Torbjørn 

[daan]

Thanks ! It was indeed when the interface is idle (CS high)