51单片机内部两路ADC采集 -

void ADC_Init(void)
{
KEY_GPIO_ADC_SET(); //设置IO为ADC功能
BAT_GPIO_ADC_SET();
ADCON = AST(0) | ADIE(0) | HTME(7) | VSEL(ADC_REF_VDD); //设置ADC参考电压
ADOPC = GAIN(NO_AMP);
}
float read_adc(unsigned char adc_ch)
{
unsigned int AD_Value;
ADCFGL = ACKD(7) | ADCALE(1) | ADCHS(adc_ch); //选择ADC通道
ADCON |= AST(1); //启动ADC转换
while(!(ADCON & ADIF));//等待转换完成
ADCON |= ADIF; //清除中断标志
AD_Value = ADCDH*256 + ADCDL; //读取AD值
AD_Value >>= 4;
VDD_Voltage = ((double)AD_Value*3.0)/4095;
return VDD_Voltage;
}

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void TIMER0_ISR (void) interrupt 1 //定时10ms
{
TH0 = TH_VAL; //高8位装初值
TL0 = TL_VAL; //低8位装初值
key1_readStatus();
key2_readStatus();
if(key1_event == SINGLE_KEY) //单击
{
key1_single_flag = 1;
}
else if(key1_event == DOUBLE_KEY) //双击
{
key1_double_flag = 1;
}
else if(key1_event == LONG_KEY) //长按
{
key1_long_flag = 1;
}
/****************************************/
if(key2_event == SINGLE_KEY) //单击
{
key2_single_flag = 1;
}
else if(key2_event == DOUBLE_KEY) //双击
{
key2_double_flag = 1;
}
else if(key2_event == LONG_KEY) //长按
{
key2_long_flag = 1;
}
}

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void key1_readStatus(void)
{
switch(key1_state)
{
case KEY_STATUS_0: //无按键按下
if(key1_flag) //如果按键1按下
{
key1_state = KEY_STATUS_1; //进入下一状态：消抖
key1_event = NO_KEY; //第一次按键按下，事件为空
}
else
{
key1_state = KEY_STATUS_0; //回到无按键状态或者第二次按下前状态
key1_event = NO_KEY;
}
break;
case KEY_STATUS_1: /* 消抖 */
if(key1_flag) //如果按键1按下
{
key1_state = KEY_STATUS_2; //进入下一状态：继续按下
key1_event = NO_KEY;
}
else
{
key1_state = KEY_STATUS_0; //回到初始状态
key1_event = NO_KEY;
}
break;
case KEY_STATUS_2: /* 确认按下 */
if(key1_flag && key1_count >= KEY_LONG_TIME)
{
key1_state = KEY_STATUS_3; //进入下一状态：长按
key1_event = NO_KEY;
key1_count = 0;
}
else if(key1_flag && key1_count < KEY_LONG_TIME)
{
key1_count++;
key1_state = KEY_STATUS_2; //进入下一状态：确认按下
key1_event = NO_KEY;
}
else
{
key1_count = 0;
key1_state = KEY_STATUS_4; //进入下一状态：等待第二次按下
key1_event = NO_KEY;
}
break;
case KEY_STATUS_3: //长按状态
if(key1_flag)
{
key1_state = KEY_STATUS_3; //一直等待按键放开
key1_event = NO_KEY;
key1_count = 0;
}
else
{
key1_state = KEY_STATUS_0;
key1_event = LONG_KEY;
key1_count = 0;
}
break;
case KEY_STATUS_4: /* 等待第二次按下 */
if(!key1_flag&&key1_count>=KEY_WAIT_TIME) //如果按键松开，且时间大于等待第二次按下的时间
{
key1_count = 0;
key1_state = KEY_STATUS_0;
key1_event = SINGLE_KEY; //判定为单击
}
else if(!key1_flag&&key1_count<KEY_WAIT_TIME)
{
key1_count++;
key1_state = KEY_STATUS_4; //继续等待
key1_event = NO_KEY;
}
else
{
key1_count = 0;
key1_state = KEY_STATUS_5; //第二次按下，且时间未到
key1_event = NO_KEY;
}
break;
case KEY_STATUS_5: /* 第二次按下 */
if(key1_flag && key1_count >= KEY_LONG_TIME)
{
key1_state = KEY_STATUS_3; //第二次按下，时间大于长按时间
key1_event = SINGLE_KEY; //先响应单击
key1_count = 0;
}
else if(key1_flag && key1_count < KEY_LONG_TIME)
{
key1_count++;
key1_state = KEY_STATUS_5; //等待按键松开
key1_event = NO_KEY;
}
else
{
key1_count = 0;
key1_state = KEY_STATUS_0; //等待按键松开
key1_event = DOUBLE_KEY; //判定为双击
}
break;
default:break;
}
}

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void key_scan(void)
{
float key_press;
key_press = read_adc(8);
if(key_press >=0&&key_press<1.0) //按键1
{
key1_flag = 1;
key2_flag = 0;
}
else if(key_press >=1.45&&key_press <1.65) //按键2
{
key2_flag = 1;
key1_flag = 0;
}
else if(key_press >2.9) //无按键
{
key1_flag = 0;
key2_flag = 0;
}
}

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while（1）
{
key_scan();//读取电压，判断是那个按键按下
if(key1_double_flag) //双击旋转屏幕
{
key1_double_flag = 0;
something();
}
else if(key1_long_flag)//长按当前通道清零
{
key1_long_flag = 0;
something();
}
}

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