单片机项目20-8×8LED点阵.docxVIP

单片机学习项目项目20-8×8LED点阵一：电路仿真点阵式LED屏驱动电路分列驱动和行驱动，在占用单片机较少I/O口资源情况下，选用串口芯片作为LED点阵显示屏的驱动接口。为了更详细的说明LED点阵驱动原理，我们先看一个8×8点阵模块驱动电路。图6-4-5所示是一种字符显示的个8×8点阵模块驱动仿真电路，8条列线和8条行线分别利用74HC595输出，其中U3为列驱动，Q7为高位，输出显示的数据，U2为行扫描，Q0接点阵的行扫描先C0。驱动电路与单片机连接只用3条数据线。下面设计程序，让点阵电路仿真显示0~9数字。二：程序设计74HC595是一种带有锁存输出功能的移位寄存器，可以实现8位串行数据到并行数据的转换，通过级联也可以实现多位数据的并行转换。本例中显示一帧图像需要发送列数据，即字符显示数据，又要发送行扫描数据，因此程序中需要设计一个发送1字节数据函数和一个锁存函数。由于要控制每帧图像显示时间，所以又要用到单片机的定时器中断。点阵显示秒时间0~9数字程序如下：/*预处理*/#includereg51.hunsigned charscan[] = {0xfe,0xfd,0xfb,0xf7,0xef,0xdf,0xbf,0x7f};unsigned intcp1,cp2,cp3;unsigned chardianzhen[10][8] ={?{0x00,0x1C,0x22,0x22,0x22,0x22,0x22,0x1C},//0{0x00,0x08,0x18,0x08,0x08,0x08,0x08,0x3C},//1{0x00,0x1C,0x02,0x02,0x1C,0x20,0x20,0x1C},//2{0x00,0x1C,0x22,0x02,0x0C,0x02,0x22,0x1C},//3{0x00,0x0C,0x14,0x14,0x24,0x3E,0x04,0x04},//4{0x00,0x1C,0x20,0x20,0x1C,0x02,0x02,0x1C},//5{0x00,0x1C,0x20,0x20,0x1C,0x22,0x22,0x1C},//6{0x00,0x3E,0x02,0x02,0x04,0x08,0x08,0x08},//7{0x00,0x1C,0x22,0x22,0x1C,0x22,0x22,0x1C},//8{0x00,0x1C,0x22,0x22,0x1C,0x02,0x02,0x1C},//9};????//0~9字符数组sbit scp = P0^0;sbit sd = P0^1;sbit sct = P0^2;/*发送一字节数据*/void send(unsignedchar x){unsigned char i;for(i = 0;i 8;i++){scp = 0;sd = (bit)(x 0x80);//高位在前x = x 1;scp = 1;}}/*74HC595锁存输出*/void suocun(void){sct = 0;sct = 1;}/*定时器中断服务函数*/voidtimer0_isr(void) interrupt 1{TH0 = (65535 - 2000) / 256;TL0 = (65535 - 2000) % 256;cp1++;if(cp1 = 8)cp1 = 0;cp2++;if(cp2 500)//1秒{cp2=0;cp3++;if(cp3= 10) //10秒cp3 = 0;}send(scan[cp1]);????????????//先发送行扫描send(dianzhen[cp3][cp1]);????//后发送8位列数据，与行扫描对应的列数据suocun();??????????????????//行列控制器锁存输出，每帧图像显示时间为2毫秒}/*定时器中断初始化函数*/voidtimer0_init(void){TMOD = 0x01;TH0 = (65535 - 2000) / 256;TL0 = (65535 - 2000) % 256;EA = 1;ET0 = 1;TR0 = 1;}void main(void){timer0_init();while(1);}?