一、概述
MAX7219/MAX7221是一种集成化的串行输入/输出共阴极显示驱动器,它连接微处理器与8位数字的7段数字LED显示，也可以连接条线图显示器或者64个独立的LED。其上包括一个片上的B型BCD编码器、多路扫描回路，段字驱动器，而且还有一个8*8的静态RAM用来存储每一个数据。只有一个外部寄存器用来设置各个LED的段电流。MAX7221与SPI™、QSPI™以及 MICROWIRE™相兼容，同时它有限制回转电流的段驱动来减少EMI（电磁干扰）。一个方便的四线串行接口可以联接所有通用的微处理器。每个数据可以寻址在更新时不需要改写所有的显示。MAX7219/MAX7221同样允许用户对每一个数据选择编码或者不编码。整个设备包含一个150μA的低功耗关闭模式，模拟和数字亮度控制，一个扫描限制寄存器允许用户显示1-8位数据，还有一个让所有LED发光的检测模式。在应用时要求3V的操作电压或segment blinking，可以查阅MAX6951数据资料。
二、应用
条线图显示 仪表面板 工业控制 LED矩阵显示
三、管脚配置
四、功能特点
10MHz 连续串行口
独立的LED 段控制
数字的译码与非译码选择
150μA 的低功耗关闭模式
亮度的数字和模拟控制
高电压中断显示
共阴极LED 显示驱动
限制回转电流的段驱动来减少EMI（MAX7221）
SPI, QSPI, MICROWIRE串行接口（MAX7221）
24 脚的DIP 和SO 封装
五、分类信息
芯片 工作温度范围 管脚封装
MAX7219CNG 0°C to +70°C 24 Narrow Plastic DIP
MAX7219CWG 0°C to +70°C 24 Wide SO
MAX7219C/D 0°C to +70°C Dice*
MAX7219ENG -40°C to +85°C 24 Narrow Plastic DIP
MAX7219EWG -40°C to +85°C 24 Wide SO
MAX7219ERG -40°C to +85°C 24 Narrow CERDIP
五、典型应用电路
六、功能图表
七、时序图
MAX7219原理图
MAX7219驱动程序
#include <reg51.h>
#include <intrins.h>
#define uchar unsigned char
#define uint unsigned int
//定义Max7219端口
sbit Max7219_pinCLK = P2^2;
sbit Max7219_pinCS = P2^1;
sbit Max7219_pinDIN = P2^0;
uchar code disp1[38][8]={
{0x3C,0x42,0x42,0x42,0x42,0x42,0x42,0x3C},//0
{0x10,0x18,0x14,0x10,0x10,0x10,0x10,0x10},//1
{0x7E,0x2,0x2,0x7E,0x40,0x40,0x40,0x7E},//2
{0x3E,0x2,0x2,0x3E,0x2,0x2,0x3E,0x0},//3
{0x8,0x18,0x28,0x48,0xFE,0x8,0x8,0x8},//4
{0x3C,0x20,0x20,0x3C,0x4,0x4,0x3C,0x0},//5
{0x3C,0x20,0x20,0x3C,0x24,0x24,0x3C,0x0},//6
{0x3E,0x22,0x4,0x8,0x8,0x8,0x8,0x8},//7
{0x0,0x3E,0x22,0x22,0x3E,0x22,0x22,0x3E},//8
{0x3E,0x22,0x22,0x3E,0x2,0x2,0x2,0x3E},//9
{0x8,0x14,0x22,0x3E,0x22,0x22,0x22,0x22},//A
{0x3C,0x22,0x22,0x3E,0x22,0x22,0x3C,0x0},//B
{0x3C,0x40,0x40,0x40,0x40,0x40,0x3C,0x0},//C
{0x7C,0x42,0x42,0x42,0x42,0x42,0x7C,0x0},//D
{0x7C,0x40,0x40,0x7C,0x40,0x40,0x40,0x7C},//E
{0x7C,0x40,0x40,0x7C,0x40,0x40,0x40,0x40},//F
{0x3C,0x40,0x40,0x40,0x40,0x44,0x44,0x3C},//G
{0x44,0x44,0x44,0x7C,0x44,0x44,0x44,0x44},//H
{0x7C,0x10,0x10,0x10,0x10,0x10,0x10,0x7C},//I
{0x3C,0x8,0x8,0x8,0x8,0x8,0x48,0x30},//J
{0x0,0x24,0x28,0x30,0x20,0x30,0x28,0x24},//K
{0x40,0x40,0x40,0x40,0x40,0x40,0x40,0x7C},//L
{0x81,0xC3,0xA5,0x99,0x81,0x81,0x81,0x81},//M
{0x0,0x42,0x62,0x52,0x4A,0x46,0x42,0x0},//N
{0x3C,0x42,0x42,0x42,0x42,0x42,0x42,0x3C},//O
{0x3C,0x22,0x22,0x22,0x3C,0x20,0x20,0x20},//P
{0x1C,0x22,0x22,0x22,0x22,0x26,0x22,0x1D},//Q
{0x3C,0x22,0x22,0x22,0x3C,0x24,0x22,0x21},//R
{0x0,0x1E,0x20,0x20,0x3E,0x2,0x2,0x3C},//S
{0x0,0x3E,0x8,0x8,0x8,0x8,0x8,0x8},//T
{0x42,0x42,0x42,0x42,0x42,0x42,0x22,0x1C},//U
{0x42,0x42,0x42,0x42,0x42,0x42,0x24,0x18},//V
{0x0,0x49,0x49,0x49,0x49,0x2A,0x1C,0x0},//W
{0x0,0x41,0x22,0x14,0x8,0x14,0x22,0x41},//X
{0x41,0x22,0x14,0x8,0x8,0x8,0x8,0x8},//Y
{0x0,0x7F,0x2,0x4,0x8,0x10,0x20,0x7F},//Z
{0x8,0x7F,0x49,0x49,0x7F,0x8,0x8,0x8},//中
{0xFE,0xBA,0x92,0xBA,0x92,0x9A,0xBA,0xFE},//国
};
void Delay_xms(uint x)
{
uint i,j;
for(i=0;i<x;i++)
for(j=0;j<112;j++);
}
//--------------------------------------------
//功能：向MAX7219(U3)写入字节
//入口参数：DATA
//出口参数：无
//说明：
void Write_Max7219_byte(uchar DATA)
{
uchar i;
Max7219_pinCS=0;
for(i=8;i>=1;i--)
{
Max7219_pinCLK=0;
Max7219_pinDIN=DATA&0x80;
DATA=DATA<<1;
Max7219_pinCLK=1;
}
}
//-------------------------------------------
//功能：向MAX7219写入数据
//入口参数：address、dat
//出口参数：无
//说明：
void Write_Max7219(uchar address,uchar dat)
{
Max7219_pinCS=0;
Write_Max7219_byte(address); //写入地址，即数码管编号
Write_Max7219_byte(dat); //写入数据，即数码管显示数字
Max7219_pinCS=1;
}
void Init_MAX7219(void)
{
Write_Max7219(0x09, 0x00); //译码方式：BCD码
Write_Max7219(0x0a, 0x03); //亮度
Write_Max7219(0x0b, 0x07); //扫描界限；8个数码管显示
Write_Max7219(0x0c, 0x01); //掉电模式：0，普通模式：1
Write_Max7219(0x0f, 0x00); //显示测试：1；测试结束，正常显示：0
}
void main(void)
{
uchar i,j;
Delay_xms(50);
Init_MAX7219();
while(1)
{
for(j=0;j<38;j++)
{
for(i=1;i<9;i++)
Write_Max7219(i,disp1[j][i-1]);
Delay_xms(1000);
}
}
}
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