Simple SPI

[verulia]

Hello,

I am using nrf9160 and want to test the just simple SPI function. The code that I found from github(https://github.com/Rallare/fw-nrfconnect-nrf/tree/nrf9160_samples/samples/nrf9160/spi c) is old and gives me too many errors. Are there any simple SPI code that I can try in my nrf9160 board in order to test whether I can send a simple data via SPI. I also found spi_flash_at45 however I don't have any device from at45 family to test it so another simple example would be so helpful for me. 

Thank you

[Håkon Alseth]

Hi,

 

Generic test code for nRF5340 can be found here:

https://devzone.nordicsemi.com/f/nordic-q-a/67065/how-to-configure-and-setup-an-spi-device-to-nrf5340/276687

 

I added some small modifications to the above sample, as SPI0 is shared with UART0/TWIM0 etc on nRF9160:

4520.simple_spi_test_nrf9160.zip

 

Kind regards,

Håkon

[verulia]

Hi,

Thank you for the fast reply. I just ran the code however I am always receiving 0 in the RX_recv. Shouldn't the value in RX_recv be similar with TX_sent since this code is just tries to send a value and receive it back as far as I understood? I didn't make any change in the code yet.

Q2:

I want to send data from nrf9160 to an external device, in order to just make a simple test before implementing a flash driver, I want to test the pins and spi, for that I am using scana to check the signals coming from spi ports. My question here is that how can I send my data to scana rather than making a loopback. For instance first I have to ad a chip select for scana, adding ss=<13> to the overlay file can be the first step right? What should I change other than this?

Thank you

[verulia]

Okey, I will try it right now thank you. Also can I directly wire miso to mosi on nrf9160? Is that what you mean?

[Håkon Alseth]

Hi,

 

This is the overlay file defined for the board "nrf9160dk_nrf9160ns":

&spi3 {
	compatible = "nordic,nrf-spim";
	status = "okay";
	sck-pin = <10>;
	mosi-pin = <11>;
	miso-pin = <12>;
};

 

if you connect the MOSI (master out - slave in) to the MISO (master in - slave out), then you will effectively loop back the sent data back to the nRF.

In the above case, its P0.11 and P0.12 that needs to be connected together.

 

Kind regards,

Håkon

[verulia]

Hi,

Yes! Thank you that worked. However I didn't understand your explanation for the ss-pin part. Do you mean that I should define an gpio pin manually for chip select. I just want to observe the clk, mosi and miso in scana sq50 and for that I have to provide a chip select connection to scana..

[Håkon Alseth]

The /SS pin is to be set active prior to the SPI transaction, and back to idle again when the transaction is done, as shown in this section on wiki (the timing diagram):

https://en.wikipedia.org/wiki/Serial_Peripheral_Interface#Clock_polarity_and_phase

 

Since its active low, you clear the /SS-pin, start the transfer, and set it high again when transfer is finished.

[verulia]

Hi,

How can I change the gpio pins? I wanted to change miso and mosi pins to p0.00 and p0.01 and wrote mosi_pin=<00>

misp_pin=<01> to the overlay file. I also add CONFIG_GPIO=y in the proj.conf file but it didn't work. Should I also add

dev = device_get_binding("GPIO_0");
gpio_pin_configure(dev, 0, GPIO_DIR_OUT);//to enable P0.00 

gpio_pin_configure(dev, 1, GPIO_DIR_OUT); //to enable P0.01

Is it sufficient? What changes should I make also? Thank you for the help. I am very new to this nrfsdk and trying to understand how it is working, for my project.

[verulia]

Hi,

Also I am trying to observe the clk signal coming from pin <10> however I can't see it from the logic analyzer too. Should I also add something to code in order to observe the clk signal.

[Håkon Alseth]

Hi,

 

Are you using the nRF9160-DK?

If yes, then some of the GPIOs are used for specific tasks. You can flip the kit over to see which GPIOs are used (ie. routed) to a specific use.

This is also shown in the kit user guide: https://infocenter.nordicsemi.com/topic/ug_nrf91_dk/UG/nrf91_DK/board_controller.html?cp=2_0_5_4_6_0

 

verulia said:

How can I change the gpio pins? I wanted to change miso and mosi pins to p0.00 and p0.01 and wrote mosi_pin=<00>

misp_pin=<01> to the overlay file. I also add CONFIG_GPIO=y in the proj.conf file but it didn't work. Should I also add

 P0.00 and P0.01 is used for UART on the DK, so you should avoid using these gpios on the nRF9160-DK.

 

Kind regards,

Håkon

[verulia]

Hi,

Yes I know, however I need to change the pins. Which ones should I use then? Also is the way that I am doing right for changing the pins? Because it didn't work when I just wrote  mosi_pin=<0> and miso_pin<1> should I also need to add gpio_set or gpio_config to change the spi pins?

[verulia]

Hi,

Also I am trying to observe the clk signal coming from pin <10> however I can't see it from the logic analyzer too. Should I also add something to code in order to observe the clk signal.

[Håkon Alseth]

The peripheral, when active, will claim the pins. No need for you to manually configure it.

Have you tried other GPIOs, like switching the MISO/MOSI/CLK pins? For instance, you see the MOSI signal on P0.12, and no clk on P0.10. Try to switch these and then scope the signal.

 

Which nRF9160-DK version do you have?

 

Kind regards,

Håkon