[NRF52840] SPI and SPIS example!

RE: [NRF52840] SPI and SPIS example!

MainOFF — Tue, 31 Oct 2017 13:07:51 GMT

thanks you. I am going to try your solution right now

RE: [NRF52840] SPI and SPIS example!

Sigurd — Tue, 31 Oct 2017 11:51:19 GMT

That is correct. You should set this up as a interrupt (trigger a interrupt when the GPIO level changes), so that the master don’t have to check the pin all the time.

RE: [NRF52840] SPI and SPIS example!

MainOFF — Tue, 31 Oct 2017 08:59:06 GMT

I config one pin of Slave board is output ( Pin P0.1). This Pin also connect to Master board as input. If slave board has data to send, It write 0 ( or 1) to Pin 0.1.If master board read Pin0.1 == 0, It know Slave want to send data. Then Master send some dummy byte to Slave to receive response. Am I correct?

RE: [NRF52840] SPI and SPIS example!

Sigurd — Tue, 31 Oct 2017 08:43:37 GMT

You can use a GPIO pin for that.

RE: [NRF52840] SPI and SPIS example!

MainOFF — Tue, 31 Oct 2017 05:47:26 GMT

Yes. Thanks for your reply! If I " want to get clever and have the slave raise a separate interrupt when it has data it wants to send", how can I do?

RE: [NRF52840] SPI and SPIS example!

RK — Tue, 31 Oct 2017 05:01:11 GMT

No you can't do that. SPI's clock is controlled by the master. If it's not clocking, no data flows, that's just the basic definition of the protocol.

The master can clock out null data constantly if it wants to read from the slave and work out if there is valid data, but that's it, the slave can't initiate a transfer in SPI. If you want to get clever and have the slave raise a separate interrupt when it has data it wants to send, you could do that, but still the master needs to drive the actual transfer of SPI data.