ZigBee_ADC数据位

ADC通道（ channel）与引脚是一一对应的关系，即每个ADC通道都有固定的与之对应的引脚。
有内部通道和外部通道之分。

模拟传感器：
value = ADCL >> 2 ; //将采集到低6位赋值到7~2中（5-0），ADCH(13-6)
value |= ((uint16) ADCH) << 6 ; //得到整个寄存器的值，最高位是符号位
value <<= 1; //湮没符号位
value >>= 3; //将所得数值送到低八位，准备转

//CC253x采集电池电压（内部通道VDD/3）：  
#if defined (HAL_MCU_CC2430) || defined (HAL_MCU_CC2530)

  uint16 value;

  /* Clear ADC interrupt flag */
  ADCIF = 0;

  ADCCON3 = (HAL_ADC_REF_125V | HAL_ADC_DEC_128 | HAL_ADC_CHN_VDD3);

  /* Wait for the conversion to finish */
  while ( !ADCIF );

  /* Get the result */
  value = ADCL;
  value |= ((uint16) ADCH) << 8;

  /*
   * value now contains measurement of Vdd/3
   * 0 indicates 0V and 32767 indicates 1.25V
   * voltage = (value*3*1.25)/32767 volts
   * we will multiply by this by 10 to allow units of 0.1 volts
   */

  value = value >> 6;   // divide first by 2