使用金沙滩51单片机实现——用AD测量DA，按键可以调整DA值，AD测量到模拟量后液晶显示模拟量
我们基于一个极为相似的官方工程，三下五除二改一下
下面代码是main函数代码部分。
视频效果：
使用金沙滩51单片机实现——用AD测量DA，按键可以调整DA值，AD测量到模拟量后液晶显示模拟量
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471882291main.c：
#include <reg52.h>sbit ADDR0 = P1^0;
sbit ADDR1 = P1^1;
sbit ADDR2 = P1^2;
sbit ADDR3 = P1^3;
sbit ENLED = P1^4;
sbit KEY1 = P2^4;
sbit KEY2 = P2^5;
sbit KEY3 = P2^6;
sbit KEY4 = P2^7;sbit KEY_OUT_4 = P2^0;
bit flag300ms = 1; //300ms定时标志
unsigned char T0RH = 0; //T0重载值的高字节
unsigned char T0RL = 0; //T0重载值的低字节
unsigned char code LedChar[] = { //数码管显示字符转换表0xC0, 0xF9, 0xA4, 0xB0, 0x99, 0x92, 0x82, 0xF8,0x80, 0x90, 0x88, 0x83, 0xC6, 0xA1, 0x86, 0x8E
};
unsigned char LedBuff[6] = { //数码管显示缓冲区，初值0xFF确保启动时都不亮0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF
};
int keynum=0,mode=0;
void ConfigTimer0(unsigned int ms);
unsigned char GetADCValue(unsigned char chn);
extern void I2CStart();
extern void I2CStop();
extern unsigned char I2CReadACK();
extern unsigned char I2CReadNAK();
extern bit I2CWrite(unsigned char dat);
extern void InitLcd1602();
extern void LcdShowStr(unsigned char x, unsigned char y, unsigned char *str);
extern void LCD_ShowNum(unsigned char Line,unsigned char Column,unsigned int number,unsigned char length);
void Delay_ms(int ms) //@11.0592MHz
{unsigned char i;while(ms--){for(i=0;i<113;i++);}
}
/* 设置DAC输出值，val-设定值 */
void SetDACOut(unsigned char val)
{I2CStart();if (!I2CWrite(0x48<<1)) //寻址PCF8591，如未应答，则停止操作并返回{I2CStop();return;}I2CWrite(0x40); //写入控制字节I2CWrite(val); //写入DA值 I2CStop();
}
/* 按键驱动函数，检测按键动作，调度相应动作函数，需在主循环中调用 */
unsigned char Key_GetNum(void)
{unsigned char KeyNum = 0; //定义变量，默认键码值为0if(KEY1==0){Delay_ms(18);while (KEY1==0); //等待按键松手Delay_ms(18);KeyNum = 1; }if(KEY2==0){Delay_ms(18);while (KEY2==0); //等待按键松手Delay_ms(18);KeyNum = 2; }if(KEY3==0){Delay_ms(18);while (KEY3==0); //等待按键松手Delay_ms(18);KeyNum = 3; }if(KEY4==0){Delay_ms(18);while (KEY4==0); //等待按键松手Delay_ms(18);KeyNum = 4; }return KeyNum; //返回键码值，如果没有按键按下，所有if都不成立，则键码为默认值0
}void main()
{unsigned char val;EA = 1; //开总中断ENLED = 0; //使能U3，选择控制数码管//ADDR3 = 1; //因为需要动态改变ADDR0-2的值，所以0-2不需要初始化了ConfigTimer0(2); //配置T0定时2msInitLcd1602();KEY_OUT_4=0;while (1){keynum=Key_GetNum( );if (flag300ms){flag300ms = 0;//显示通道0的电压val = GetADCValue(0); //获取ADC通道0的转换值val = (val*25) / 255; //电压值=转换结果*2.5V/255，式中的25隐含了一位十进制小数LCD_ShowNum(1, 1, val,6);}if(keynum==2){mode+=50;}SetDACOut(mode);}
}
/* 读取当前的ADC转换值，chn-ADC通道号0~3 */
unsigned char GetADCValue(unsigned char chn)
{unsigned char val;I2CStart();if (!I2CWrite(0x48<<1)) //寻址PCF8591，如未应答，则停止操作并返回0{I2CStop();return 0;}I2CWrite(0x40|chn); //写入控制字节，选择转换通道I2CStart();I2CWrite((0x48<<1)|0x01); //寻址PCF8591，指定后续为读操作 I2CReadACK(); //先空读一个字节，提供采样转换时间val = I2CReadNAK(); //读取刚刚转换完的值I2CStop();return val;
}
/* 配置并启动T0，ms-T0定时时间 */
void ConfigTimer0(unsigned int ms)
{unsigned long tmp; //临时变量tmp = 11059200 / 12; //定时器计数频率tmp = (tmp * ms) / 1000; //计算所需的计数值tmp = 65536 - tmp; //计算定时器重载值tmp = tmp + 12; //补偿中断响应延时造成的误差T0RH = (unsigned char)(tmp>>8); //定时器重载值拆分为高低字节T0RL = (unsigned char)tmp;TMOD &= 0xF0; //清零T0的控制位TMOD |= 0x01; //配置T0为模式1TH0 = T0RH; //加载T0重载值TL0 = T0RL;ET0 = 1; //使能T0中断TR0 = 1; //启动T0
}
/* T0中断服务函数，执行数码管动态显示、300ms定时 */
void InterruptTimer0() interrupt 1
{static unsigned char i = 0; //动态扫描的索引static unsigned char tmr300ms = 0; //300ms软件定时计数器TH0 = T0RH; //重新加载重载值TL0 = T0RL;tmr300ms++;if (tmr300ms >= 150) //定时300ms{tmr300ms = 0;flag300ms = 1;}}