前面介绍过在pcDuino上运行LED Matrix Kit，这个套件中有MAX7219芯片，它是串行输入/输出共阴极数码管显示驱动芯片，它的操作很简单，MCU只需通过模拟SPI三线接口就可以将相关的指令写入MAX7219的内部指令和数据寄存器，而且它还支持多片7219串联，即可以通过3根线控制更多的数码管显示。

封装引脚图：

在Arduino下级联三片LED Matrix 点阵屏

CLK   –> arduino D8

每片LED显示频率在驱动程序里可以设置，程序代码如下

#define uchar unsigned charint Max7219_CLK = 8;int Max7219_CS = 9;int Max7219_DIN = 10;uchar num[16][8] = {{0x1C,0x22,0x22,0x22,0x22,0x22,0x22,0x1C},//0{0x08,0x18,0x28,0x08,0x08,0x08,0x08,0x3E},//1{0x3E,0x02,0x02,0x3E,0x20,0x20,0x20,0x3E},//2{0x3E,0x02,0x02,0x3E,0x02,0x02,0x02,0x3E},//3{0x0C,0x14,0x24,0x3E,0x04,0x04,0x04,0x04},//4{0x3E,0x20,0x20,0x3E,0x02,0x02,0x02,0x3E},//5{0x3E,0x20,0x20,0x3E,0x22,0x22,0x22,0x3E},//6{0x3E,0x02,0x04,0x08,0x08,0x08,0x08,0x08},//7{0x1C,0x22,0x22,0x1C,0x22,0x22,0x22,0x1C},//8{0x3E,0x22,0x22,0x3E,0x02,0x02,0x02,0x3E},//9{0x08,0x14,0x22,0x22,0x3E,0x22,0x22,0x22},//A{0x3C,0x22,0x22,0x3C,0x22,0x22,0x22,0x3C},//B{0x1C,0x22,0x20,0x20,0x20,0x20,0x22,0x1C},//C{0x38,0x24,0x22,0x22,0x22,0x22,0x24,0x38},//D{0x3E,0x20,0x20,0x3E,0x20,0x20,0x20,0x3E},//E{0x3E,0x20,0x20,0x3E,0x20,0x20,0x20,0x20},//F};void write_byte(uchar DATA){uchar i;digitalWrite(Max7219_CS,LOW);for(i=8;i>=1;i--){digitalWrite(Max7219_CLK,LOW);digitalWrite(Max7219_DIN,DATA&0x80);//提取Data的高一位数据 DATA = DATA<<1;digitalWrite(Max7219_CLK,HIGH);}}void write_first(uchar address,uchar dat){digitalWrite(Max7219_CS,LOW);write_byte(address);           //写入地址，即数码管编号 write_byte(dat);               //写入数据，即数码管显示数字  digitalWrite(Max7219_CS,HIGH);}void write_second(char address,char dat){digitalWrite(Max7219_CS,LOW);write_byte(address);           //写入地址，即数码管编号 write_byte(dat);               //写入数据，即数码管显示数字  write_byte(0);write_byte(0);digitalWrite(Max7219_CS,HIGH);}void write_third(char address,char dat){digitalWrite(Max7219_CS,LOW);write_byte(address);           //写入地址，即数码管编号 write_byte(dat);               //写入数据，即数码管显示数字  write_byte(0);write_byte(0);write_byte(0);write_byte(0);digitalWrite(Max7219_CS,HIGH);}void max7219_init(void){write_first(0x09, 0x00);       //译码方式：BCD码 write_first(0x0a, 0x03);       //亮度  write_first(0x0b, 0x07);       //扫描界限；8个数码管显示 write_first(0x0c, 0x01);       //掉电模式：0，普通模式：1 write_first(0x0f, 0x00);       //显示测试：1；测试结束，正常显示：0 write_second(0x09, 0x00);       //译码方式：BCD码 write_second(0x0a, 0x03);       //亮度  write_second(0x0b, 0x07);       //扫描界限；8个数码管显示 write_second(0x0c, 0x01);       //掉电模式：0，普通模式：1 write_second(0x0f, 0x00);       //显示测试：1；测试结束，正常显示：0 write_third(0x09, 0x00);       //译码方式：BCD码 write_third(0x0a, 0x03);       //亮度  write_third(0x0b, 0x07);       //扫描界限；8个数码管显示 write_third(0x0c, 0x01);       //掉电模式：0，普通模式：1 write_third(0x0f, 0x00);       //显示测试：1；测试结束，正常显示：0 }void setup(){pinMode(Max7219_CLK,OUTPUT);pinMode(Max7219_CS,OUTPUT);pinMode(Max7219_DIN,OUTPUT);max7219_init();}void loop(){uchar i,count;while(1){for(i=1;i<9;i++){write_first(i,num[count/100][i-1]);write_second(i,num[count%100/10][i-1]);write_third(i,num[count%10][i-1]);}delay(200);count++;}}