Suggestion needed for mcp23s17 code on NCS 3.2.4.

Question

I have init spi4- for

 spi4_default: spi4_default {
        group1 {
            psels = <NRF_PSEL(SPIM_SCK, 1, 15)>,
                    <NRF_PSEL(SPIM_MISO, 1, 14)>,
                    <NRF_PSEL(SPIM_MOSI, 1, 13)>;
        };
    };

    spi4_sleep: spi4_sleep {
        group1 {
            psels = <NRF_PSEL(SPIM_SCK, 1, 15)>,
                    <NRF_PSEL(SPIM_MISO, 1, 14)>,
                    <NRF_PSEL(SPIM_MOSI, 1, 13)>;
            low-power-enable;
        };
    };

&spi4 {
    compatible = "nordic,nrf-spim";
    status = "okay";

    pinctrl-0 = <&spi4_default>;
    pinctrl-1 = <&spi4_sleep>;
    pinctrl-names = "default", "sleep";

    cs-gpios = <&gpio0 31 GPIO_ACTIVE_LOW>;


     mcp23s17: gpio_expander@0 {
        compatible = "microchip,mcp23s17";
        reg = <0>;

        spi-max-frequency = <1000000>;
        spi-hold-cs;
        gpio-controller;
        #gpio-cells = <2>;

        ngpios = <16>;

        status = "okay";
    };
}

static const struct device *mcp =
    DEVICE_DT_GET(DT_NODELABEL(mcp23s17));

char pinconf = 0;

void testextend()
{
    int ret;
    uint32_t val;

    if (!device_is_ready(mcp))
    {
        printk("MCP not ready\n");
        return;
    }

    if (pinconf == 0)
    {
        for (int i = 0; i < 16; i++)
        {
            ret = gpio_pin_configure(mcp, i, GPIO_OUTPUT_ACTIVE);
            printk("CFG PIN %d RET=%d\n", i, ret);
        }

        pinconf = 1;
    }

    /* ACTIVE LOW LED -> 0 = ON */

    ret = gpio_pin_set(mcp, 13, 0);
    printk("PIN13 ON RET=%d\n", ret);

    ret = gpio_pin_set(mcp, 14, 0);
    printk("PIN14 ON RET=%d\n", ret);

    ret = gpio_pin_set(mcp, 15, 0);
    printk("PIN15 ON RET=%d\n", ret);

    ret = gpio_port_get_raw(mcp, &val);
    printk("LED ON RAW = 0x%04X\n", val);

    k_sleep(K_SECONDS(1));

    /* ACTIVE LOW LED -> 1 = OFF */

    ret = gpio_pin_set(mcp, 13, 1);
    printk("PIN13 OFF RET=%d\n", ret);

    ret = gpio_pin_set(mcp, 14, 1);
    printk("PIN14 OFF RET=%d\n", ret);

    ret = gpio_pin_set(mcp, 15, 1);
    printk("PIN15 OFF RET=%d\n", ret);

    ret = gpio_port_get_raw(mcp, &val);
    printk("LED OFF RAW = 0x%04X\n", val);

    k_sleep(K_SECONDS(1));
}

Complete hardware is fine, Yet SPI communication is not happening, Am I missing something? I did nothing extra than this.

Shubham Vilayatkar · Accepted Answer

Hi Benjamin,

I waited for your answer, but I have resolved an issue. In the nRF5340_PS_v16.pdf it is mentioned that for SPIM4 "The GPIO must use the high drive H0H1 configuration in the DRIVE field of the PIN_CNF GPIO register."

With default S0S1, we were not able to communicate with MCP23S17.

Solution is -

 spi4_default: spi4_default {
        group1 {
            psels = <NRF_PSEL(SPIM_SCK, 1, 15)>,
                    <NRF_PSEL(SPIM_MISO, 1, 14)>,
                    <NRF_PSEL(SPIM_MOSI, 1, 13)>;
                    nordic,drive-mode = <NRF_DRIVE_H0H1>;
        };
    };

Suggestion needed for mcp23s17 code on NCS 3.2.4.

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