关于msp430f149的12adc采集问题

 参考这个代码

VCC 作为 参考

/* --COPYRIGHT--,BSD_EX
 * Copyright (c) 2012, Texas Instruments Incorporated
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * *  Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * *  Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * *  Neither the name of Texas Instruments Incorporated nor the names of
 *    its contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 *******************************************************************************
 * 
 *                       MSP430 CODE EXAMPLE DISCLAIMER
 *
 * MSP430 code examples are self-contained low-level programs that typically
 * demonstrate a single peripheral function or device feature in a highly
 * concise manner. For this the code may rely on the device's power-on default
 * register values and settings such as the clock configuration and care must
 * be taken when combining code from several examples to avoid potential side
 * effects. Also see www.ti.com/grace for a GUI- and www.ti.com/msp430ware
 * for an API functional library-approach to peripheral configuration.
 *
 * --/COPYRIGHT--*/
//******************************************************************************
//  MSP-FET430P140 Demo - ADC12, Sample A0, Set P1.0 if A0 > 0.5*AVcc
//
//  Description: A single sample is made on A0 with reference to AVcc.
//  Software sets ADC10SC to start sample and conversion - ADC12SC
//  automatically cleared at EOC. ADC12 internal oscillator times sample (16x)
//  and conversion. In Mainloop MSP430 waits in LPM0 to save power until ADC12
//  conversion complete, ADC12_ISR will force exit from LPM0 in Mainloop on
//  reti. If A0 > 0.5*AVcc, P1.0 set, else reset.
//
//                MSP430F149
//             -----------------
//         /|\|              XIN|-
//          | |                 |
//          --|RST          XOUT|-
//            |                 |
//      Vin-->|P6.0/A0      P1.0|--> LED
//
//  M. Buccini
//  Texas Instruments Inc.
//  Feb 2005
//  Built with CCE Version: 3.2.0 and IAR Embedded Workbench Version: 3.21A
//******************************************************************************

#include <msp430.h>

int main(void)
{
  WDTCTL = WDTPW + WDTHOLD;                 // Stop WDT
  ADC12CTL0 = SHT0_2 + ADC12ON;             // Set sampling time, turn on ADC12
  ADC12CTL1 = SHP;                          // Use sampling timer
  ADC12IE = 0x01;                           // Enable interrupt
  ADC12CTL0 |= ENC;                         // Conversion enabled
  P6SEL |= 0x01;                            // P6.0 ADC option select
  P1DIR |= 0x01;                            // P1.0 output

  for (;;)
  {
    ADC12CTL0 |= ADC12SC;                   // Sampling open
    __bis_SR_register(CPUOFF + GIE);        // LPM0, ADC12_ISR will force exit
  }
}

// ADC12 interrupt service routine
#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector=ADC12_VECTOR
__interrupt void ADC12_ISR (void)
#elif defined(__GNUC__)
void __attribute__ ((interrupt(ADC12_VECTOR))) ADC12_ISR (void)
#else
#error Compiler not supported!
#endif
{
    if (ADC12MEM0 < 0x7FF)
      P1OUT &= ~0x01;                       // Clear P1.0 LED off
    else
      P1OUT |= 0x01;                        // Set P1.0 LED on
    __bic_SR_register_on_exit(CPUOFF);      // Clear CPUOFF bit from 0(SR)

我的adc设置为：（采用了多次测量）

void Init_ADC(void)
{
P6SEL |= 0x01; // 使能ADC通道
ADC12CTL0 = ADC12ON + SHT0_10 + MSC; // 打开ADC，设置采样时间
ADC12CTL1 = SHP + CONSEQ_2; // 使用采样定时器

for ( int k=0; k<0x3600;k++){} //等待电压稳定

ADC12IE = 0x01; // 使能ADC中断
ADC12CTL0 |= ENC; // 使能转换
ADC12CTL0 |= ADC12SC; // 开始转换
}

在中断处理里面，就是连续进行了32次采样，并求取平均值，具体为：

#pragma vector=ADC_VECTOR
__interrupt void ADC12ISR (void)
{
static uchar index = 0;

results[index++] = ADC12MEM0; // Move results
// average=ADC12MEM0;
if(index == Num_of_Results)
{
uchar i;
average = 0;
for(i = 0; i < Num_of_Results; i++)
{
average += results[i];
}
average >>= 5; //测量32次，除以32，求品均值
index = 0;
tcnt++;
if(tcnt == 250) //主要是降低串口发送速度
{
LPM1_EXIT;
tcnt = 0;
}
}
}

就会出现这种情况。求助

你好，请问这个问题你是这么解决的？

/*********************************************************
程序功能：将ADC对P6.0端口电压的转换结果按转换数据和对应的
模拟电压的形式通过串口发送到PC机屏幕上显示
-----------------------------------------------------------
通信格式：N.8.1, 9600
-----------------------------------------------------------
测试说明：打开串口调试精灵，正确设置通信格式，观察接收数据
**********************************************************/
#include <msp430.h>
#include "allfunc.h"
#include "UART0_Func.c"
#include "ADC_Func.c"

#define Num_of_Results 16
uint results[Num_of_Results]; //保存ADC转换结果的数组
uint average;
uchar tcnt = 0;

/***********************主函数***********************/
void main( void )
{
uchar i;
uchar buffer[5];

WDTCTL = WDTPW + WDTHOLD; //关狗

/*下面六行程序关闭所有的IO口*/
P1DIR = 0XFF;P1OUT = 0XFF;
P2DIR = 0XFF;P2OUT = 0XFF;
P3DIR = 0XFF;P3OUT = 0XFF;
P4DIR = 0XFF;P4OUT = 0XFF;
P5DIR = 0XFF;P5OUT = 0XFF;
P6DIR = 0XFF;P6OUT = 0XFF;

P6DIR |= BIT2;P6OUT |= BIT2; //关闭电平转换
P6DIR|=BIT6;P6OUT&=~BIT6; //关闭数码管显示

InitUART();
Init_ADC();
_EINT();

buffer[4] = '\0';
while(1)
{
LPM1;
Hex2Dec(average,buffer);
for(i = 0; i < 4; i++)
buffer[i] += 0x30;
PutString0("The digital value is: ");
PutString(buffer);


Trans_val(average,buffer);
buffer[3] = buffer[2];
buffer[2] = buffer[1];
buffer[1] = 0x2e - 0x30;
for(i = 0; i < 4; i++)
buffer[i] += 0x30;
PutString0("The analog value is: ");
PutString(buffer);
}

}

/*******************************************
函数名称：ADC12ISR
功 能：ADC中断服务函数，在这里用多次平均的
计算P6.0口的模拟电压数值
参 数：无
返回值 ：无
********************************************/
#pragma vector=ADC_VECTOR
__interrupt void ADC12ISR (void)
{
static uchar index = 0;

results[index++] = ADC12MEM0; // Move results
if(index == Num_of_Results)
{
uchar i;

average = 0;
for(i = 0; i < Num_of_Results; i++)
{
average += results[i];
}
average >>= 4; //除以32

index = 0;
tcnt++;
if(tcnt == 250) //主要是降低串口发送速度
{
LPM1_EXIT;
tcnt = 0;
}
}
}

我也这样尝试了，确实是这样的，修改为16次采集一次