fet140_adc12_09.c

msp430的C语言示例 来自TI官方

//******************************************************************************
//  MSP-FET430P140 Demo - ADC12, 序列转换(非重复) (non-repeated)
//
//  Description: This example shows how to perform A/D conversions on a sequence
//  of channels. A single sequence of conversions is performed - one conversion
//  each on channels A0, A1, A2, and A3. Each conversion uses AVcc and AVss for
//  the references. The conversion results are stored in ADC12MEM0, ADC12MEM1,
//  ADC12MEM2, and ADC12MEM3 respectively and are moved to 'results[]' upon
//  completion of the sequence. Test by applying voltages to pins A0, A1, A2,
//  and A3, then setting and running to a break point at the "_BIC..."
//  instruction in the ISR. To view the conversion results, open a watch window
//  in debugger and view 'results' or view ADC12MEM0, ADC12MEM1, ADC12MEM2, and
//  ADC12MEM3 in an ADC12 SFR window.

//  Note that a sequence has no restrictions on which channels are converted.
//  For example, a valid sequence could be A0, A3, A2, A4, A2, A1, A0, and A7.
//  See the MSP430x1xx User's Guide for instructions on using the ADC12.
//
//
//                MSP430F149
//            -----------------
//           |                 |
//   Vin0 -->|P6.0/A0          |
//   Vin1 -->|P6.1/A1          |
//   Vin2 -->|P6.2/A2          |
//   Vin3 -->|P6.3/A3          |
//           |                 |
//
//
//  M. Mitchell
//  Texas Instruments Inc.
//  Feb 2005
//  Built with IAR Embedded Workbench Version: 3.21A
//******************************************************************************

#include  <msp430x14x.h>

static unsigned int results[4];             // Needs to be global in this example
                                            // Otherwise, the compiler removes it
                                            // because it is not used for anything.

void main(void)
{
  WDTCTL = WDTPW+WDTHOLD;                   // 停止看门狗
  P6SEL = 0x0F;                             // 打开A0-A3 A/D通道输入
  ADC12CTL0 = ADC12ON+MSC+SHT0_2;           // 开ADC12模块+采样信号由SHI仅首次触发
					    //+采集定时器分频系数n=4,

  ADC12CTL1 = SHP+CONSEQ_1;                 // 使用采样定时器输出作采集/转换信号SAMPCON
					    // +序列单次采样模式
  ADC12MCTL0 = INCH_0;                      // 参考电压ref+=AVcc, 输入通道选择为 A0
  ADC12MCTL1 = INCH_1;                      // 参考电压ref+=AVcc, 输入通道选择为 A1
  ADC12MCTL2 = INCH_2;                      // 参考电压ref+=AVcc, 输入通道选择为 A2
  ADC12MCTL3 = INCH_3+EOS;                  // 参考电压ref+=AVcc, 输入通道选择为 A3,+由此通道产生序列结束控制位
  ADC12IE = 0x08;                           // A3通道开中断ADC12IFG.3
  ADC12CTL0 |= ENC;                         // 允许转换

  while(1)
  {
  ADC12CTL0 |= ADC12SC;                     // 启动转换
  _BIS_SR(LPM0_bits + GIE);                 // 进入LPM0, 开总中断允许
  }
}

#pragma vector=ADC_VECTOR
__interrupt void ADC12ISR (void)
{
  results[0] = ADC12MEM0;                   // 移动A0转换结果往全局数组，此操作的同时清除ADC12FIG.0
  results[1] = ADC12MEM1;                   // 移动A1转换结果往全局数组，此操作的同时清除ADC12FIG.1
  results[2] = ADC12MEM2;                   // 移动A2转换结果往全局数组，此操作的同时清除ADC12FIG.2
  results[3] = ADC12MEM3;                   // 移动A3转换结果往全局数组，此操作的同时清除ADC12FIG.3
  _BIC_SR_IRQ(LPM0_bits);                   // 退出LPM0