[经验]

请问STM32F411CUE6是如何使用SPI+DMA驱动ws2812b节点的

fansz

2022-8-26 17:35:19

5776 SPI接口 STM32F4 WS2812B

SPI 配置成 13.333MHZ (我使用开发板是：STM32F411CUE6最小开发板，SPI的通讯频率我测试过 2.5Mhz、3.333Mhz、6.666Mhz、13.333Mhz, 最终选择13.333Mhz的原因:这个稳定)

2byte(MCU) == 1bit(ws2812b)

1个ws2812b节点需要 2 x 8 x 3 = 48字节因此，太多节点的人，请谨慎使用。

ws2812.h

@Author: maplerian
@Date: 2020-07-11 16:03:03
@LastEditors: maplerian
@LastEditTime: 2020-07-11 16:53:52
@Description: file content

*/

#ifndef WS2812__H

#define WS2812__H

#include <rtthread.h>

#include <rtdevice.h>

// 一位占用多少个字节

#define OneBitOccupyByte 2

#define OneNodeBuffLength 8 * 3 * OneBitOccupyByte

struct ws2812

{

struct rt_spi_device *spi;

uint8_t *buff;

uint16_t node_len;

};

typedef struct ws2812 * ws2812_t;

ws2812_t ws2812_create(char *spi_name, uint16_t led_node_length);

void ws2812_clear_buff(ws2812_t ws2812);

void ws2812_write_rgb_to_node(ws2812_t ws2812, uint16_t index, uint8_t r, uint8_t g, uint8_t b);

void ws2812_write_rgb_to_all(ws2812_t ws2812, uint8_t r, uint8_t g, uint8_t b);

void ws2812_send(ws2812_t ws2812);

#endif //!WS2812__H

ws2812.c

@Author: maplerian
@Date: 2020-07-11 16:02:23
@LastEditors: maplerian
@LastEditTime: 2020-07-11 17:23:30
@Description: file content

*/

#include "ws2812.h"

ws2812_t ws2812_create(char *spi_name, uint16_t led_node_length)

{

if (!spi_name || !led_node_length)

return RT_NULL;

struct rt_spi_device *spi = (struct rt_spi_device *)rt_device_find(spi_name);

if (spi == RT_NULL)

return RT_NULL;

ws2812_t ws2812 = (ws2812_t)rt_malloc(sizeof(struct ws2812));

ws2812->buff = (uint8_t *)rt_malloc(OneNodeBuffLength * led_node_length);

if (!ws2812->buff)

{

rt_kprintf("There is not enough memory to create a buffer.
");

rt_free(ws2812);

return RT_NULL;

}

// 配置 spi

struct rt_spi_configuration ws2812_spi_config;

ws2812_spi_config.mode = RT_SPI_MASTER | RT_SPI_MODE_0 | RT_SPI_MSB; // 高位在前

ws2812_spi_config.max_hz = 13 * 1000 * 1000 + 333 * 1000; // 200ns / bit => 8bit 1.6us => 1.25us < 1.6us < 1.85us 可行 6M 3b = 500ns 5b = 833ns

ws2812_spi_config.data_width = 8;

rt_spi_configure((struct rt_spi_device *)spi, &ws2812_spi_config);

// 赋值

ws2812->spi = spi;

ws2812->node_len = led_node_length;

return ws2812;

}

void ws2812_clear_buff(ws2812_t ws2812)

{

if (!ws2812 || !ws2812->buff || !ws2812->node_len)

return;

rt_memset(ws2812->buff, 0x00, OneNodeBuffLength * ws2812->node_len);

}

// 写颜色节点颜色到缓冲区 // 2byte == 1bit

void ws2812_write_buff(uint8_t *buff, uint8_t r, uint8_t g, uint8_t b)

{

uint32_t rgb = g << 24 | r << 16 | b << 8;

uint8_t i = 24;

while (i--)

{

// bit 1: 1111 1111 1110 0000

if (rgb & 0x80000000)

{

*buff++ = 0xff;

*buff++ = 0xe0;

}

// bit 0: 1111 1000 0000 0000

else

{

*buff++ = 0xf8;

*buff++ = 0x00;

}

//