编码开关程序

#include
sbit BMA = P1^4;//编码开关A引脚
sbit BMB = P1^5;//编码开关B引脚
sbit BMC = P1^6;//编码开关 下按引脚

unsigned char display[3];
unsigned char code LEDData[ ] = {
0xC0,0xF9,0xA4,0xB0,0x99,0x92,
0x82,0xF8,0x80,0x90,0xff
};
unsigned char counter = 0; //编码器脉冲计数
unsigned char n,shift;

/**********************************************************

ms延时子函数

**********************************************************/
void delayms(unsigned int ms)
{
unsigned char k;

while (ms--)
{
for (k = 0; k < 114; k++)
;
}
}

/**********************************************************

扫描编码器子函数

在编码器引脚A为低电平期间：

编码器引脚B从0到1为正转，编码器引脚B从1到0为反转。

**********************************************************/
void scan_encoder(void)
{
static bit Curr_b; //定义一个变量来储存当前B信号
static bit Last_b; //定义一个变量来储存上次B脚信号
static bit update= 0;

if( BMA && BMB) //编码器无转动退出
{
update = 0;
return;
}

Last_b = BMB; //记录B信号

while(!BMA) //等待A由低变高
{
Curr_b = BMB; //记录等待期间的B信号(指当前B信号)
update = 1;

if(!BMC) //当按下旋钮时
{
counter = 0; //计数单元清零(归位)
delayms(10);
}


}

if(update)
{
update = 0 ;
if( (Last_b == 0)&&(Curr_b== 1) ) //B从0到1为正转
{
if(counter == 255)
return;
counter++; //正转计数加
}
else if( (Last_b == 1)&&(Curr_b == 0) ) //B从1到0为反转
{
if(counter == 0)
return;
counter--; //反转计数减
}
}
}

/**********************************************************

主函数

**********************************************************/
void main(void)
{
P0 = 0xff;
P1 = 0xff;
P2 = 0xff;

T2CON = 0x00; //设置T2CON寄存器
TH2 = 0xfc; //1ms定时
TL2 = 0x66;
ET2 = 1; //启用Timer2中断
EA = 1; //总中断允许
TR2 = 1; //启动定时器2
counter = 0; //计数单元清零

while(1)
{

scan_encoder();
if(!BMC) //当按下旋钮时
{
counter = 0; //计数单元清零(归位)
delayms(10);
}
}
}

/*********************************************************

Timer2中断函数

**********************************************************/
void timer2() interrupt 5
{
TR2 = 0;
TF2 = 0; //手工清中断标志
TH2 = 0xfc;

//1ms定时常数
TL2 = 0x66;

if(n >= 3) //3位数码管显示
{
n = 0;
shift = 0x7f; //送位码初值
P2 = 0xff; //关闭显示
}
else
{
display[0] = counter%10; //个位数据
display[1] = (counter%100)/10; //十位数据
display[2] = counter/100; //百位数据

if(display[2] == 0)
{
display[2] = 0x0a; //百位为0,不显示
if(display[1] == 0)
display[1] =0x0a; //十位为0,不显示
}

P0 = LEDData[display[n++]]; //送段码
P2 = shift; //送位码
shift = (shift>>1)|0x80; //调整位码
}
TR2 = 1;
}

/*********************************************************/