SPI VS UART For Minimal Data Transfer & Sleep

RE: SPI VS UART For Minimal Data Transfer & Sleep

snoopy20 — Fri, 31 Jul 2020 11:59:58 GMT

For some reason I can't close based on your answer, but yes I'm sticking with SPI. There is another advantage, the slave device (in my case a PIC16) can use the pin clk and fully Sleep until the buffer is read.

RE: SPI VS UART For Minimal Data Transfer & Sleep

Simonr — Fri, 31 Jul 2020 11:43:26 GMT

UART with EasyDMA will draw quite a bit of current as you say, so I think I would lean towards SPI in this case as well. If you, by sd_sleep routine, mean the nRF's sleep, then that will indeed be interrupted if you're triggering UART I believe, so you won't be able to stay asleep while the UART is running. Indeed, the SPI will keep the HF clock running until it is finished.

Best regards,

Simon

RE: SPI VS UART For Minimal Data Transfer & Sleep

snoopy20 — Thu, 30 Jul 2020 19:04:37 GMT

It looks like I'm sticking with SPI, there are no power advantages over UART from what I can see. This assumes the transaction is triggered by PPI via a timer and afterwards the CPU tries to enter sleep mode (the HF won't turn off until the SPI transaction is over, I think).