C8051的ADC使用

void ADC0_Init(void)                   //初始化ADC
{
    P0MDIN  &= 0xF3; // set P0.2 P0.3 as an analog input
    P0SKIP  |= 0x0C;                    // skip P0.2 P0.3 pin
}

void Timer2_Init (void)                 //定时器
{
   TMR2CN  = 0x00;                      // Stop Timer2; Clear TF2;   选择为16位定时器
                                        // use SYSCLK as timebase, 16-bit 
                                        // auto-reload
   CKCON   = 0x30;                      // select SYSCLK for timer 2 source   选择为系统时钟
   TMR2RL  =  - (SYSCLK / 10800/12);   // init reload value for 10uS  设置中断的频率
   TMR2    = 0xffff;                    // set to reload immediately
   TR2     = 1;                         // start Timer2                启动工作
}

void SetADC0_Init (void)                   //ADC初始化
{
   ADC0CN = 0x03;                      // ADC0 disabled, normal tracking, T2益出中断触发 
                                       // conversion triggered on TMR2 overflow
   REF0CN = 0x93;                      // Enable on-chip VREF = 2.2v and buffer  IDAMRG=1合并IDAC0、IDAC1
                                       //电压基准选择为2.2V且输出在VREF引脚
   ADC0MX = 0x02;    // Set P0.2 as positive input  选择P0.2通道输入

   ADC0CF = ((SYSCLK/3000000)-1)<<3;   // set SAR clock to 3MHz  选择ADC时钟为3MHZ

   ADC0CF |= 0x00;                     // right-justify results 

   EIE1 |= 0x08;                       // enable ADC0 conversion complete int.  势能ADC转换完成中断