SDK 15.0 SPIM Example Issue on nRF52840

RE: SDK 15.0 SPIM Example Issue on nRF52840

aeozyalcin — Thu, 12 Mar 2020 05:22:02 GMT

I have actually since moved from SPIM #3 that is the default on the examples to SPIM #0. I disabled SPIM#3 and the extended options in the makefile, and enabled SPIM#0. However, still having the same issues. With SPIM#0, I am using the following:

APP_ERROR_CHECK(nrfx_spim_xfer(&spi, &xfer_desc, 0));

RE: SDK 15.0 SPIM Example Issue on nRF52840

hmolesworth — Thu, 12 Mar 2020 02:09:32 GMT

Ah, I think you have DCX set (if NRFX_SPIM_DCX_PIN is defined as a pin and NRFX_SPIM_EXTENDED_ENABLED) but are using the non-DCX transfer function which never sets the expected length. If so maybe try this:

 APP_ERROR_CHECK(nrfx_spim_xfer_dcx(&spi, &xfer_desc, 0, 15)); // 15 is the example

RE: SDK 15.0 SPIM Example Issue on nRF52840

aeozyalcin — Thu, 12 Mar 2020 00:17:18 GMT

Thanks for replying. I agree with what you are saying, and I am aware of this nuance. However unfortunately, the problem somehow lies within how the interrupts are handled in my case, and the event handler not being called. This information might help others though.

RE: SDK 15.0 SPIM Example Issue on nRF52840

aeozyalcin — Thu, 12 Mar 2020 00:15:40 GMT

Thanks for the reply Simon. I have some updates:

When I don't pass a function for the SPI event handler, such that I initialize SPIM like this:

APP_ERROR_CHECK(nrfx_spim_init(&spi, &spi_config, NULL, NULL));

Without interrupts, I am able to get SPIM to work. Looks like the issue lies somewhere within how the interrupts are handled. I have looked through the SDK documents, but can't figure out what I might be doing wrong. Any idea why event handler interrupts are not being handled? I am pretty sure that when I have the event handler passed into the SPIM init function, the function itself never gets called, and the SPI transaction stalls after the data bits are sent out without SS getting de-asserted. Thanks!

RE: SDK 15.0 SPIM Example Issue on nRF52840

hmolesworth — Mon, 09 Mar 2020 15:15:22 GMT

This seems to be a common mistake when using SPI, covered quite a few times here on the devzone so maybe worth looking through some of those posts. In brief the received data is actually the 2nd byte, not the 1st byte. Change this:

    if (m_rx_buf[0] != 0)

to this:

    if (m_rx_buf[1] != 0)

mrxbuf must of course be at least 2 bytes long, and the requested received data length must be at least 2 bytes; 1 byte will not work as the SPI slave doesn't know what data to send until it has received and decoded the first transmitted byte.

RE: SDK 15.0 SPIM Example Issue on nRF52840

Simonr — Mon, 09 Mar 2020 13:50:59 GMT

Have you adapted the example to run on the Dongle? Please check out the Dongle Programming tutorial and the Adapt a simple example (without SoftDevice) section to see how to adapt your project to fit the Dongle.

Best regards,

Simon