Difference between revisions of "Matrix - RGB LED"

Revision as of 15:19, 23 June 2016

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1 Introduction

• Matrix-RGB_LED是一个RGB发光二极管模块。5-Pin 2.54mm排针，V接电源，G接地，R、G、B引脚分别控制二极管发出红、绿、蓝三种颜色的光，或者组合发出混色光。
• 您可以向R、G、B引脚输出静态的高低电平信号，也可以输出变化的PWM信号，信号电平可以是3.3V或5V。当您向R、G、B引脚输出高电平时LED以最大亮度发光，低电平就完全熄灭；向R、G、B引脚输出可变占空比的PWM信号可以调节R、G、B颜色光发光的亮度，从而形成多种颜色的混色光。

2 Features

• GPIO或PWM控制，3.3/5V电平，亮度通过PWM可调
• Small
• 2.54 mm pitch pin-header
• PCB dimension(mm): 16 x 24

• Pin Description:

3 工作原理

• RGB_LED的内部封装了三颗不同颜色的灯珠，三个灯珠的阳极或者阴极并联，当给另外三个引脚施加控制信号时，对应的LED就会亮起。当两种或三种LED亮起时，根据三原色原理，会组成其他颜色的光。施加PWM信号时，不同占空比的PWM信号可以调节R、G、B颜色光发光的亮度，从而组合成多种颜色。

4 Applications

4.1 Connect to NanoPi M1

Refer to the following connection diagram to connect the module to the NanoPi M1:

Connection Details:

4.2 Connect to NanoPi 2

Refer to the following connection diagram to connect the module to the NanoPi 2:

Connection Details:

4.3 Connect to NanoPi M2 / NanoPi 2 Fire

Refer to the following connection diagram to connect the module to the NanoPi M2/ NanoPi 2 Fire.

Connection Details:

4.4 Connect to NanoPC-T2

Refer to the following connection diagram to connect the module to the NanoPC-T2:
Matrix-RGBLED_NanoPC-T2

Connection Details:

5 编译运行测试程序

启动开发板并运行Debian系统，进入系统后克隆Matrix代码仓库：

$ apt-get update && apt-get install git
$ git clone https://github.com/friendlyarm/matrix.git

克隆完成后会得到一个名为matrix的目录。

编译并安装Matrix：

$ cd matrix
$ make && make install

运行测试程序：

$ matrix-rgb_led

注意：此模块并不支持热插拔，启动系统前需要确保硬件连接正确。
运行效果如下：

Set RGB LED: 0
Set RGB LED: 1
Set RGB LED: 2
Set RGB LED: 3
Set RGB LED: 4
Set RGB LED: 5
Set RGB LED: 6
Set RGB LED: 7

可以看到RGBLED在不停地变换颜色。

6 代码说明

所有的开发板都共用一套Matrix代码，本模块的测试示例代码为matrix-rgb_led，内容如下:

int main(int argc, char ** argv)
{
    int ret = -1;
    int val, board;
 
    if ((board = boardInit()) < 0) {
        printf("Fail to init board\n");
        return -1;
    }
    if (board == BOARD_NANOPI_T2) {
        ledPin1 = GPIO_PIN(15);
        ledPin2 = GPIO_PIN(16);
        ledPin3 = GPIO_PIN(17);
    }
    if ((ret = exportGPIOPin(ledPin1)) == -1) {
        printf("exportGPIOPin(%d) failed\n", ledPin1);
    }
    if ((ret = setGPIODirection(ledPin1, GPIO_OUT)) == -1) {
        printf("setGPIODirection(%d) failed\n", ledPin1);
    }
    if ((ret = exportGPIOPin(ledPin2)) == -1) {
        printf("exportGPIOPin(%d) failed\n", ledPin2);
    }
    if ((ret = setGPIODirection(ledPin2, GPIO_OUT)) == -1) {
        printf("setGPIODirection(%d) failed\n", ledPin2);
    }
    if ((ret = exportGPIOPin(ledPin3)) == -1) {
        printf("exportGPIOPin(%d) failed\n", ledPin3);
    }
    if ((ret = setGPIODirection(ledPin3, GPIO_OUT)) == -1) {
        printf("setGPIODirection(%d) failed\n", ledPin3);
    }
    signal(SIGINT, intHandler);
    for (val = 0; val < 8; val++) {
        printf("Set RGB LED: %x\n", val);
        setRGBLED(val);
        usleep(1000 * 1000);
    }
    unexportGPIOPin(ledPin1);
    unexportGPIOPin(ledPin2);
    unexportGPIOPin(ledPin3);
    return 0;
}

API说明参考维基：Matrix API reference manual

7 相关资料