CSN event trigger on nRF51822

[Bogdan]

Hi, I'm trying to implement a specific communication protocol using the SPI on a nRF51822. The SPI on nordic side will act as slave. When CSN line goes low, I will also need to do other processing (setup other GPIO pins to indicate specific states).

Is there a way to setup CSN line to also trigger an event by using GPIOTE? According to the documentation, when the pin is controlled by GPIOTE, other operations on that pin will have no effect.

If the pin cannot be used like that, is there a way for the SPIS to not use CSN line? Act like it's the only slave on the SPI and get data on each CLK edge (ignoring the CSN line)?

Thank you

[Stian Røed Hafskjold]

Is there a way to setup CSN line to also trigger an event by using GPIOTE? According to the documentation, when the pin is controlled by GPIOTE, other operations on that pin will have no effect.

Could you just assign CSN to one pin and GPIOTE event to another pin and connect those pins together physically? So that 'chip select' from master both trigger the CSN and GPIOTE event?

If the pin cannot be used like that, is there a way for the SPIS to not use CSN line? Act like it's the only slave on the SPI and get data on each CLK edge (ignoring the CSN line)?

SPIS needs the CSN line to acquire and release the semaphore that enables sharing of the RXD and TXD buffers between the SPIS and the CPU.

[Bogdan]

Thanks for the reply. Indeed, I've connected CSN with another GPIO and it works.

[Stian Røed Hafskjold]

I'm glad it works! If you feel your question has been answered, please accept the answer so we can close the thread