Struggling to use SPI with Zephyr

RE: Struggling to use SPI with Zephyr

Håkon Alseth — Tue, 15 Oct 2024 06:54:27 GMT

Hi,

This thread is quite old, so if you run into any issues, I highly recommend that you open a new thread.

[quote user="s23"]but I have a question regarding your devicetree overlay for the NRF5340 DK, specifically the code below:[/quote]

reg-my-spi-master is just a name given to a node under the "my_spi_master" device, which in this case is &spi4.

This is referenced in main.c.

If you look at parts of the nordic dev academy, especially this section on the i2c, you can see a similar approach when implementing a application specific sensor: https://academy.nordicsemi.com/courses/nrf-connect-sdk-fundamentals/lessons/lesson-6-serial-com-i2c/topic/i2c-driver/

Kind regards,

Håkon

RE: Struggling to use SPI with Zephyr

s23 — Sun, 13 Oct 2024 07:07:22 GMT

Hi ovrebekk

Apologies for chiming in on this years later, but I have a question regarding your devicetree overlay for the NRF5340 DK, specifically the code below:

my_spi_master: &spi4 {
	compatible = "nordic,nrf-spim";
	status = "okay";
	pinctrl-0 = <&spi_master_default>;
	pinctrl-1 = <&spi_master_sleep>;
	pinctrl-names = "default", "sleep";
	cs-gpios = <&gpio0 7 GPIO_ACTIVE_LOW>;
	reg_my_spi_master:  spi-dev-a@0 {
		reg = <0>;
	};
};

What does the following code relate to? I cannot find any reference of reg_my_spi_master or spi-dev-a?

Regards

RE: Struggling to use SPI with Zephyr

ovrebekk — Mon, 07 Nov 2022 20:28:05 GMT

Hi Duncan

Glad I could help. A big thanks to you for pointing out the mistake in the example 🙂

Best regards
Torbjørn

RE: Struggling to use SPI with Zephyr

DunKCubik — Mon, 07 Nov 2022 13:28:40 GMT

Hi ovrebekk,

thanks for your reply. I'll check out the update later on. Many thanks for your help, I'm up to speed on SPI now!

Duncan

RE: Struggling to use SPI with Zephyr

ovrebekk — Mon, 07 Nov 2022 12:49:00 GMT

Hi Duncan

Thanks for the update, it seems I was using the device_is_ready(..) function incorrectly. Most zephyr functions return an int, but this one returns a bool, so I had to change the example a little.

If you check out my latest update I have corrected this.

The overlay warnings I can see here also, but they don't seem to affect the example. I will try to find some time later to look into this.

Best regards
Torbjørn

RE: Struggling to use SPI with Zephyr

DunKCubik — Fri, 04 Nov 2022 12:40:17 GMT

Hi, got your example to build Ok and I have connected the MISO and MOSI pins between master and slave. My build config is for the nrf52840dk and the overlay file is correctly loaded

Getting the following from terminal output.

*** Booting Zephyr OS build v3.1.99-ncs1 ***
SPI master device not ready!
SPI master chip select device not ready!
SPI slave device not ready!
SPI master/slave example started
SPI SLAVE TX: 0x00, 0x00
SPI TX: 0x00, 0x00

and this from the overlay file..

def-char = <0x00>;

"Property not mentioned in \"nordic,nrf-spi\"",

reg_my_spi_master: spi-dev-a@0

"Node spi-dev-a should have \"compatible\" property",
"Node should only occur on the undefined bus.",

Any ideas why it's not working?

Cheers

Duncan

RE: Struggling to use SPI with Zephyr

ovrebekk — Thu, 03 Nov 2022 17:08:59 GMT

Hi Duncan

So glad to hear the example was helpful.

The best of luck with your project 🙂

Best regards
Torbjørn

RE: Struggling to use SPI with Zephyr

DunKCubik — Thu, 03 Nov 2022 13:12:36 GMT

That's great! Thanks for the example, I have managed to get something working after realising that I needed an overlay file! Your example is really good and I understand it much better now. Thank you so much.

RE: Struggling to use SPI with Zephyr

ovrebekk — Thu, 03 Nov 2022 13:02:07 GMT

Hi Duncan

You could have a look at an SPI master/slave example I made here.

I believe the issue in your case is the nodelabel. spi0 is the name of the node from the board definition, you should not use this as the label.

Rather I would try something like this:

// Overlay
my_spi: spi0 {
  // Add properties here 
};

// Source code
struct device *spiDev;  /* SPI device pointer*/
void main(void)
{
    spiDev = DEVICE_DT_GET(DT_NODELABEL(my_spi));
}

Best regards
Torbjørn