nRF52832 with SK6812 LEDs

[jablackann]

Hello,

I tried to run the example code for the ws2812 (which can be found at C:\ncs\v2.4.1\v2.4.1\zephyr\samples\drivers\led_ws2812) for the nRF52832 using nRF Connect SDK (v2.4.1).

Looking at the nrf52dk_nrf52832.overlay, it looks like MOSI would be used on P0.23.

&arduino_spi { /* MOSI on D11 / P0.23 */

I am trying to experiment using the nRF52 DK board. 
I have a known working LED ring which lights up from another board.

The code builds fine but when I run it, I see the following in the terminal.

Using a Saleae Logic analyzer, I don't see anything on P0.23. 

I tried adding the following from nrf52dk_nrf52832.dts but I ended up with the same message in the terminal and didn't see anything on the logic analyzer.

I tried multiple pins and couldn't see any changes on the IO lines that looked like the required signal for the WS2812 LEDs.

&spi2_default {

    group1 {

        psels = <NRF_PSEL(SPIM_SCK, 0, 25)>, <NRF_PSEL(SPIM_MISO, 0, 24)>,

        <NRF_PSEL(SPIM_MOSI, 0, 12)>;

    };

};

Fullscreen 3036.main.c Download

/*
 * Copyright (c) 2017 Linaro Limited
 * Copyright (c) 2018 Intel Corporation
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include <errno.h>
#include <string.h>

#define LOG_LEVEL 4
#include <zephyr/logging/log.h>
LOG_MODULE_REGISTER(main);

#include <zephyr/kernel.h>
#include <zephyr/drivers/led_strip.h>
#include <zephyr/device.h>
#include <zephyr/drivers/spi.h>
#include <zephyr/sys/util.h>

#define STRIP_NODE		DT_ALIAS(led_strip)
#define STRIP_NUM_PIXELS	DT_PROP(DT_ALIAS(led_strip), chain_length)

#define DELAY_TIME K_MSEC(50)

#define RGB(_r, _g, _b) { .r = (_r), .g = (_g), .b = (_b) }

static const struct led_rgb colors[] = {
	RGB(0x0f, 0x00, 0x00), /* red */
	RGB(0x00, 0x0f, 0x00), /* green */
	RGB(0x00, 0x00, 0x0f), /* blue */
};

struct led_rgb pixels[STRIP_NUM_PIXELS];

static const struct device *const strip = DEVICE_DT_GET(STRIP_NODE);

int main(void)
{
	size_t cursor = 0, color = 0;
	int rc;

	if (device_is_ready(strip)) {
		LOG_INF("Found LED strip device %s", strip->name);
	} else {
		LOG_ERR("LED strip device %s is not ready", strip->name);
		return 0;
	}

	LOG_INF("Displaying pattern on strip");
	while (1) {
		memset(&pixels, 0x00, sizeof(pixels));
		memcpy(&pixels[cursor], &colors[color], sizeof(struct led_rgb));
		rc = led_strip_update_rgb(strip, pixels, STRIP_NUM_PIXELS);

		if (rc) {
			LOG_ERR("couldn't update strip: %d", rc);
		}

		cursor++;
		if (cursor >= STRIP_NUM_PIXELS) {
			cursor = 0;
			color++;
			if (color == ARRAY_SIZE(colors)) {
				color = 0;
			}
		}

		k_sleep(DELAY_TIME);
	}
	return 0;
}

0334.prj.conf

nrf52dk_nrf52832.dts

Has anyone had success with the WS2812 or SK6812 with the nRF52832 and nRF Connect SDK?

Thanks.

[jablackann]

Shortly after I posted that, i found the following example on github.

https://github.com/zephyrproject-rtos/zephyr/tree/main/samples/drivers/led_ws2812

Looking at this, it states that the LED strip can be controlled either via I2S SDOUT or SPI MOSI.  I tried the I2S method.

The thingy52 says that it used the I2S method. Where the 52DK was using the SPI method (which I tried and could not get to work).

Here  is my nrf52dk_nrf52832.overlay file.

 6011.nrf52dk_nrf52832.overlay

Here is what the led ring looks like.  I can see colors flashing around the ring but it is very bright.

Here are some captures from my logic analyzer.

The logic analyzer doesn't want to decode it.  I am guessing there is something wrong with how this is work and this is causing the LED ring to be mostly white.