NRF DK Basic GPIO

RE: NRF DK Basic GPIO

Geordie — Wed, 27 Oct 2021 13:50:58 GMT

Funny enough I was already in the process of re-coding based on that very article! Got the GPIO working, although it would be nice to have done it via the dts overlay and the GPIO_DT_SPCE_GET macro, but I guess that's really now a question for the Zephyr community.

It didn't help that I was using some GPIO that was already being used for the xtal and other functionality on the nRF DK board. For future reference:

I freed up the GPIO assigned to the DK buttons and LED's by grounding the SHIELD detect header pin.

Grab a reference to the GPIO controller:

#define GPIO_PORT DEVICE_DT_GET(DT_NODELABEL(gpio0))

Grouped some IO bits together:

typedef struct gpio_s {
    struct device const *port;
    gpio_pin_t const pin;
    gpio_flags_t flags;
} gpio_t;

Grouped the 3-digit seven seg LED IO into a structure..

typedef struct three_digit_s {
    gpio_t a;
    gpio_t b;
    gpio_t c;
    gpio_t d;
    gpio_t e;
    gpio_t f;
    gpio_t g;

    gpio_t dp;
    gpio_t d1_en;
    gpio_t d2_en;
    gpio_t d3_en;
} three_digit_t;

with some static assignments specifying the pin numbers..

static three_digit_t three_digit = {
  .a = {
    .port = GPIO_PORT,
    .pin = 11,
    .flags = GPIO_OUTPUT_INACTIVE
  },
  .b = {
    .port = GPIO_PORT,
    .pin = 12,
    .flags = GPIO_OUTPUT_INACTIVE
  },
  
  ... etc
  
};

configure..

success = gpio_pin_configure(
    three_digit.a.port,
    three_digit.a.pin,
    three_digit.a.flags
  );

then set..

gpio_pin_set(
    three_digit.d1_en.port,
    three_digit.d1_en.pin,
    0   // or 1..
);

👍🏽

RE: NRF DK Basic GPIO

Simon — Tue, 26 Oct 2021 14:13:12 GMT

Could you try using this approach: https://devzone.nordicsemi.com/f/nordic-q-a/72618/extra-gpios-in-board-overlay-for-nrf9160dk?

Let me know if you get it to work or not

Best regards,

Simon

RE: NRF DK Basic GPIO

Geordie — Tue, 26 Oct 2021 08:23:05 GMT

Found the comments in include/drivers/gpio.h

/**
 * @brief Static initializer for a @p gpio_dt_spec
 *
 * This returns a static initializer for a @p gpio_dt_spec structure
 * given a devicetree node identifier and a property specifying a
 * GPIO.
 *
 * Example devicetree fragment:
 *
 *	n: node {
 *		foo-gpios = <&gpio1 2 GPIO_ACTIVE_LOW>;
 *	}
 *
 * Example usage:
 *
 *	const struct gpio_dt_spec spec = GPIO_DT_SPEC_GET(DT_NODELABEL(n),
 *							  foo_gpios);
 *	// Initializes 'spec' to:
 *	// {
 *	//         .port = DEVICE_DT_GET(DT_NODELABEL(gpio1)),
 *	//         .pin = 2,
 *	//         .dt_flags = GPIO_ACTIVE_LOW
 *	// }
 *...
 */

I changed the prop names in the dts from underscore to dash, just in case. No joy.

RE: NRF DK Basic GPIO

Geordie — Mon, 25 Oct 2021 22:17:10 GMT

I've done away with my attempt to group some IO by specifying another connector, having looked around some of the dt binding files. So I'm just left with this:

  seven_seg_display: seven_seg {
    seg_a = <&gpio0 0 0>; 
    seg_b = <&gpio0 1 0>;
    seg_c = <&gpio0 21 0>;
    seg_d = <&gpio0 5 0>;
    seg_e = <&gpio0 6 0>;
    seg_f = <&gpio0 7 0>;
    seg_g = <&gpio0 8 0>;
    dp = <&gpio0 9 0>;
    dig_1_en = <&gpio0 10 (GPIO_PULL_UP | GPIO_ACTIVE_LOW)>;
    dig_2_en = <&gpio0 11 (GPIO_PULL_UP | GPIO_ACTIVE_LOW)>;
    dig_3_en = <&gpio0 12 (GPIO_PULL_UP | GPIO_ACTIVE_LOW)>;
  };

I understand my error is complaining that the properties of this node aren't GPIO instances, but is something like this possible? I spotted this post that I'll try tomorrow that describes just getting the GPIO_0 instance and using that on the configure calls, but I'd still like to know how to use GPIO_DT_SPEC_GET() with my example.

Any help appreciated. Cheers.