RT-Thread-FRDM-MCXN947开发板之RGB LED驱动RT-Thread问答社区

FRDM-MCXN947开发板之RGB LED驱动

发布于 2024-04-26 21:07:26 浏览：240 订阅该版

[tocm]

## 一、背景

- RGB LED：通过红、绿、蓝三种颜色组合发光的LED，可以理解由三个不同发光属性的LED组成，这个是LCD平板显示原理的基础，一个LED相当于屏幕上面的一个像素

![led-module.PNG](https://oss-club.rt-thread.org/uploads/20240426/2476b8e9681e6b723dc83305b1c5a901.png.webp)

- FRDM-MCXN947集成了一块RGB LED，它由三个GPIO口驱动，这里由于GPIO的电平只能是0或者1，所以这里的RGB LED并不能像LCD的单个像素那样合成256x256x256种颜色

![board-logo.PNG](https://oss-club.rt-thread.org/uploads/20240426/525a42d8662f6cda284bc7d61bde8a62.png.webp)

## 二、颜色表

三原色合成颜色关系表如图所示

![color-table.PNG](https://oss-club.rt-thread.org/uploads/20240426/aca08b22ac56a805e5d738626407623f.png.webp)

颜色组合关系表

| 颜色 | Red  | Green | Blue | 英文名 |
| ---- | ---- | ----- | ---- | ------ |
| 红   | 1    | 0     | 0    | Red    |
| 绿   | 0    | 1     | 0    | Green  |
| 蓝   | 0    | 0     | 1    | Blue   |
| 品红 | 1    | 0     | 1    | Pink   |
| 黄   | 1    | 1     | 0    | Yellow |
| 青   | 0    | 1     | 1    | Cyan   |
| 白   | 1    | 1     | 1    | White  |

## 三、电路

电路引脚对应关系：R -> P0_10，G -> P0_27，B -> P1_2

![leds.png](https://oss-club.rt-thread.org/uploads/20240426/2a47c80e3e336d3b2b5f48c9e3c85093.png.webp)

驱动方式：上拉接VCC，通过灌电流方式接入GPIO，低电平发光

![circuit.png](https://oss-club.rt-thread.org/uploads/20240426/cdcb072e1067c78e1f2f78ca3d0bb5de.png.webp)

## 四、程序设计

初始化RGB LED

```C
#include "drv_pin.h"

#define LEDR_PIN        ((0*32)+10)
#define LEDG_PIN        ((0*32)+27)
#define LEDB_PIN        ((1*32)+2)

......

{
    rt_pin_mode(LEDR_PIN, PIN_MODE_OUTPUT);  /* Set GPIO as Output */
    rt_pin_mode(LEDG_PIN, PIN_MODE_OUTPUT);  /* Set GPIO as Output */
    rt_pin_mode(LEDB_PIN, PIN_MODE_OUTPUT);  /* Set GPIO as Output */
}
```

动态展示各种混合颜色

```C
while (1)
{
    // Red
    rt_pin_write(LEDR_PIN, PIN_LOW);  
    rt_pin_write(LEDG_PIN, PIN_HIGH);   
    rt_pin_write(LEDB_PIN, PIN_HIGH); 
    rt_thread_mdelay(delay);               
    // Green
    rt_pin_write(LEDR_PIN, PIN_HIGH); 
    rt_pin_write(LEDG_PIN, PIN_LOW);   
    rt_pin_write(LEDB_PIN, PIN_HIGH);    
    rt_thread_mdelay(delay);            
    // Blue
    rt_pin_write(LEDR_PIN, PIN_HIGH);   
    rt_pin_write(LEDG_PIN, PIN_HIGH);   
    rt_pin_write(LEDB_PIN, PIN_LOW);   
    rt_thread_mdelay(delay);              
    // Yellow
    rt_pin_write(LEDR_PIN, PIN_LOW);    
    rt_pin_write(LEDG_PIN, PIN_LOW);   
    rt_pin_write(LEDB_PIN, PIN_HIGH);   
    rt_thread_mdelay(delay);            
    // Pink
    rt_pin_write(LEDR_PIN, PIN_LOW);   
    rt_pin_write(LEDG_PIN, PIN_HIGH);   
    rt_pin_write(LEDB_PIN, PIN_LOW);   
    rt_thread_mdelay(delay);             
    // Cyan
    rt_pin_write(LEDR_PIN, PIN_HIGH);  
    rt_pin_write(LEDG_PIN, PIN_LOW);   
    rt_pin_write(LEDB_PIN, PIN_LOW);    
    rt_thread_mdelay(delay);               
    // White
    rt_pin_write(LEDR_PIN, PIN_LOW); 
    rt_pin_write(LEDG_PIN, PIN_LOW);   
    rt_pin_write(LEDB_PIN, PIN_LOW);   
    rt_thread_mdelay(delay);               
 }
```

## 五、视频

实验操作视频参考

[FRDM-MCXN947开发板之RGB灯_哔哩哔哩_bilibili](https://www.bilibili.com/video/BV1jC411G7h5/?spm_id_from=333.999.0.0&vd_source=d939b06c630702aeb499bac767324c8c)

## 六、总结

纸上得来终觉浅，绝知此事要躬行，曾经在大学学过LCD平板显示原理，知道像素的显示原理，知道三原色，但一直没有机会实操，我也不大清楚青色（cyan）居然由绿色（green）和蓝色（blue）合成的

## 七、术语

- RGB：red green blue，红色、绿色、蓝色三种颜色的通称
- LED：light emittiing diode，发光二极管
- LCD：Liquid Crystal Display，液晶显示
- pink：品红、粉红
- cyan：青色