Changing SPI frequency

RE: Changing SPI frequency

Stefan Birnir Sverrisson — Mon, 01 Sep 2014 07:42:14 GMT

I made some experiment on how to change the SPI frequency and modified the answer accordingly.

RE: Changing SPI frequency

Gili Elias — Thu, 28 Aug 2014 09:56:16 GMT

Thanks for the update. Basically, apart from the frequency, we don't need any other configuration change. The SPI close/open procedure resets a lot of the other parameters. Will it be enough to just disable and re-enable the SPI through p_nrf_spi->ENABLE, or are there other steps that needs to be taken? We want to shorten this process to the bare minimum needed for the frequency change.

RE: Changing SPI frequency

Stefan Birnir Sverrisson — Thu, 28 Aug 2014 07:09:48 GMT

You can change the frequency by writing to the struct with e.g. :

 spi_config.SPI_Freq = SPI_FREQUENCY_FREQUENCY_M4;

However, if you would like to change the SPI frequency on the fly, you can do that by writing directly to the frequency register of the SPI module that you are using, i.e.

NRF_SPI0->FREQUENCY = SPI_FREQUENCY_FREQUENCY_M4;

Make sure to change the frequency only when the SPI is not transmitting/receiving.