fet140_adc12_05.c

msp430的C语言示例 来自TI官方

//******************************************************************************
//  MSP-FET430P140 Demo - ADC12, 使用外部参考电压
//
//  Description: This example shows how to use an external positive reference for
//  the ADC12.The external reference is applied to the VeREF+ pin. AVss is used
//  for the negative reference. A single conversion is performed on channel A0.
//  The conversion results are stored in ADC12MEM0 and Test by applying a voltage
//  to channel A0, then setting and running to a break point at the "_NOP()"
//  instruction. To view the conversion results, open an SFR window in debugger 
//  and view the contents of ADC12MEM0.
//
//
//               MSP430F149
//                ---------------
//               |               |
//        Vin -->|P6.0/A0        |
//               |               |
//        REF -->|VeREF+         |
//               |               |
//
//  M. Mitchell
//  Texas Instruments Inc.
//  Feb 2005
//  Built with IAR Embedded Workbench Version: 3.21A
//******************************************************************************

#include  <msp430x14x.h>

void main(void)
{
  WDTCTL = WDTPW+WDTHOLD;                   // 停止看门狗
  P6SEL |= 0x01;                            // 打开A0 A/D通道输入
  ADC12CTL0 = ADC12ON+SHT0_2;               // 开ADC12模块+采集定时器分频系数n=4
  ADC12CTL1 = SHP;                          // 使用采样定时器输出作采集/转换信号SAMPCON
  ADC12MCTL0 = SREF_2;                      // 使用外部参考电压 Vr+ = VeREF+
  ADC12CTL0 |= ENC;                         // 允许转换

  while (1)
  {
    ADC12CTL0 |= ADC12SC;                   // 开始转换
    while ((ADC12IFG & BIT0)==0);	    //等待转换结束
    _NOP();                                 //转换完成
  }
}