Issues with SPI and nrf52dk

RE: Issues with SPI and nrf52dk

Kazi Afroza Sultana — Tue, 03 Mar 2026 12:18:49 GMT

Hello,

I am very glad that you have solved the issue and thank you so much to share this with other users.

Best Regards,

Kazi

RE: Issues with SPI and nrf52dk

federicoc — Fri, 27 Feb 2026 17:11:52 GMT

Thank you, Kazi, for guiding me in the right direction. I've uploaded a complete working solution to this GitHub repository, hoping it will assist others facing the same issue:
nrf52-zephyr-rtos-spi

After setting up CS within the SPI node configuration, I successfully established communication. No need to manually control CS. The key was to configure the SPI in the overlay file in this manner:

&spi1 {
	compatible = "nordic,nrf-spim";
	status = "okay";
    pinctrl-0 = <&spi1_default>;
    pinctrl-1 = <&spi1_sleep>;
    pinctrl-names = "default", "sleep";
    cs-gpios = <&gpio0 11 GPIO_ACTIVE_LOW>;
    spi_node: spi-dev-a@0 {
		reg = <0>;
	};
};

Thank you again and have a great weekend.

RE: Issues with SPI and nrf52dk

Kazi Afroza Sultana — Thu, 26 Feb 2026 12:44:09 GMT

Hello,

CS pin is part of any SPI node as child node so zephyr will not associate any CS with that bus. There is previous case (+) The cs pin of the spi is not working - Nordic Q&A - Nordic DevZone - Nordic DevZone you can look at.

RE: Issues with SPI and nrf52dk

federicoc — Mon, 23 Feb 2026 17:39:38 GMT

Thank you Kazi for your reply.

My understanding is that if a pin is Active Low, then passing 0U to gpio_pin_set_dt(&cs, 0U) means that we intend to set the pin to its Inactive state, which is High.
I confirmed this behavior with leds and so on, and clearly the trace from the logic analyzer shows that I am pulling the cs line low when transmitting data with the following code. And I've confirmed that If set &cs to 0U, then call tranceive and the set cs to 1U, I will not get any data transmission.

gpio_pin_set_dt(&cs, 1U);
err = spi_transceive(spi1_dev, &spi_cfg,
                 &spi_tx_buf_set, &spi_rx_buf_set);
gpio_pin_set_dt(&cs, 0U);

Now, I've updated the code as follows:

#include <stdio.h>
#include <zephyr/kernel.h>
#include <zephyr/drivers/gpio.h>
#include <zephyr/drivers/spi.h>
#include <zephyr/device.h>
#include <zephyr/devicetree.h>
#define SLEEP_TIME_MS   5000
#define LED0_NODE DT_ALIAS(led0)
#define SPI1_NODE DT_NODELABEL(spi1)
static const struct device *spi1_dev = DEVICE_DT_GET(SPI1_NODE);
static const struct gpio_dt_spec led = GPIO_DT_SPEC_GET(LED0_NODE, gpios);
static const struct gpio_dt_spec cs = GPIO_DT_SPEC_GET_OR(DT_NODELABEL(cs_one_pin), gpios, {0});
static struct spi_config spi_cfg = {
	.frequency = 1000000U,
	.operation = SPI_WORD_SET(8),
	.slave = 0
};
static void readRegister(uint8_t reg, uint8_t values[], uint8_t size)
{
	int err; 
	uint8_t tx_buffer[3];
	tx_buffer[0] = 0x80; // read operation
	tx_buffer[1] = reg;  // registry
	tx_buffer[2] = 0x00; // dummy byte for result

	struct spi_buf tx_spi_bufs[] = {
		{.buf = tx_buffer, .len = sizeof(tx_buffer)}
	};
	struct spi_buf_set spi_tx_buf_set = {
		.buffers = tx_spi_bufs, 
		.count = 1
	};
	struct spi_buf rx_spi_bufs[] = {
		{.buf = values, .len = size}
	};
	struct spi_buf_set spi_rx_buf_set = {
		.buffers = rx_spi_bufs, 
		.count = 1
	};

	gpio_pin_set_dt(&cs, 1U);
	err = spi_transceive(spi1_dev, &spi_cfg,
                     &spi_tx_buf_set, &spi_rx_buf_set);
	gpio_pin_set_dt(&cs, 0U);
	if(err > 0)
	{
		printf("Error when sending spi message!");
	}   
}
static void readChipID(void) {
	uint8_t rx_buf_chipid[4];
	readRegister(0x00, rx_buf_chipid, 3);
	printf("Received: %X, %X, %X\n", rx_buf_chipid[0], rx_buf_chipid[1], rx_buf_chipid[2]);
}
int main(void)
{
	int ret;
	bool led_state = true;
	if (!gpio_is_ready_dt(&led)) {
		return 0;
	}
	if(!device_is_ready(spi1_dev)) {
		return 0;
	}
	ret = gpio_pin_configure_dt(&led, GPIO_OUTPUT_ACTIVE);
	if (ret < 0) {
		return 0;
	}
	ret = gpio_pin_configure_dt(&cs, GPIO_OUTPUT);
	if (ret < 0) {
		return 0;
	}
	printf("Setup completed!");

	while (1) {
		ret = gpio_pin_toggle_dt(&led);
		if (ret < 0) {
			return 0;
		}
		readChipID();
		k_msleep(SLEEP_TIME_MS);
	}
	return 0;
}

and the overlay file as:

/ {
    cs_one_pin: cs-one-pin {
                compatible = "nordic,gpio-pins";
                gpios = <&gpio0 11 GPIO_ACTIVE_LOW>;
                status = "okay";
    };
};

&spi1 {
	compatible = "nordic,nrf-spi";
	status = "okay";
    pinctrl-0 = <&spi1_default>;
    pinctrl-1 = <&spi1_sleep>;
    pinctrl-names = "default", "sleep";
};

&pinctrl {
    spi1_default: spi1_default {
        group1 {
            psels = <NRF_PSEL(SPIM_SCK, 0, 31)>,
                    <NRF_PSEL(SPIM_MOSI, 0, 30)>,
                    <NRF_PSEL(SPIM_MISO, 0, 29)>;
        };
    };

    spi1_sleep: spi1_sleep {
        group1 {
            psels = <NRF_PSEL(SPIM_SCK, 0, 31)>,
                    <NRF_PSEL(SPIM_MOSI, 0, 30)>,
                    <NRF_PSEL(SPIM_MISO, 0, 29)>;
            low-power-enable;
        };
    };
};

However on nrf52dk I am receiving back the following values from the transmission:
FF FF 40
While the logic analyzer shows
FF FE 60
I am wondering what is causing this discrepancy as the correct registry value for the BMP390 is 0x60.
I have confirmed that I am able to get the correct registry value from the sensor using arduino library.
Could be this due to the following errata?

https://docs.nordicsemi.com/bundle/errata_nRF52840_EngA/page/ERR/nRF52840/EngineeringA/latest/anomaly_840_58.html

Moreover I noticed that in the example from Nordic Academy, there is no need to pull cs manually with the transceive command. Do I need to do so?

Do i need to add a node to the SPI (if so which node should I add, since I could not find a bmp390 in the library)?

Thank you again.

RE: Issues with SPI and nrf52dk

Kazi Afroza Sultana — Mon, 23 Feb 2026 09:20:33 GMT

Hello,

I can see in the overlay you have set CS pin active low. That means CS is high before the transfer (inactive state), CS is inactive while doing write+read operation. After the transfer CS will be pulled low.

/ {
 cs_one_pin: cs-one-pin {
 compatible = "nordic,gpio-pins";
 gpios = <&gpio0 11 GPIO_ACTIVE_LOW>;
 status = "okay";
 };

But in the code, you set reverse.

 gpio_pin_set_dt(&cs, 1U);
 
 do {
    err = spi_write(spi1_dev, &spi_cfg, &spi_tx_buf_set);
    if(err < 0)
    {
     break;
    }
     err = spi_read(spi1_dev, &spi_cfg, &spi_rx_buf_set);
    }
    while(false);
    gpio_pin_set_dt(&cs, 0U); 
  }

You can try to fix this by asserting CS low before transfer the data and de-assert high after the transmission.

gpio_pin_set_dt(&cs, 0U);   // CS active (low)

err = spi_transceive(spi1_dev, &spi_cfg,
                     &spi_tx_buf_set, &spi_rx_buf_set);// instead of spi_read you can use spi_transcive()

gpio_pin_set_dt(&cs, 1U);   // CS inactive (high)

In device tree overlay you have not binded spi1_default to spi1.

Try to change the device-tree following way:

&pinctrl {
    spi1_default: spi1_default {
        group1 {
            psels = <NRF_PSEL(SPIM_SCK, 0, 31)>,
                    <NRF_PSEL(SPIM_MOSI, 0, 30)>,
                    <NRF_PSEL(SPIM_MISO, 0, 29)>;
        };
    };

    spi1_sleep: spi1_sleep {
        group1 {
            psels = <NRF_PSEL(SPIM_SCK, 0, 31)>,
                    <NRF_PSEL(SPIM_MOSI, 0, 30)>,
                    <NRF_PSEL(SPIM_MISO, 0, 29)>;
            low-power-enable;
        };
    };
};

&gpio0 {
    status = "okay";
};

&gpiote0 {
    status = "okay";
};

&spi1 {
    compatible = "nordic,nrf-spi";
    status = "okay";
    pinctrl-0 = <&spi1_default>;
    pinctrl-1 = <&spi1_sleep>;
    pinctrl-names = "default", "sleep";
};

/ {
    cs_one_pin: cs-one-pin {
        compatible = "nordic,gpio-pins";
        gpios = <&gpio0 11 GPIO_ACTIVE_LOW>;
        status = "okay";
    };
};