TI中文支持网采用默认的参考电压3.3v，结果只能采集到2047-1.65v，当外部电压高于1.65时，采集的电压有变为0-2047（0-1.65v），只能采集到外部电压的一半，这是怎么回事？？？
Ling Zhu2：
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|- //| || //--|RSTXOUT|- //|| //Vin-->|P6.0/A0P1.0|--> 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 WDTADC12CTL0 = SHT0_2 + ADC12ON;// Set sampling time, turn on ADC12ADC12CTL1 = SHP;// Use sampling timerADC12IE = 0x01;// Enable interruptADC12CTL0 |= ENC;// Conversion enabledP6SEL |= 0x01;// P6.0 ADC option selectP1DIR |= 0x01;// P1.0 outputfor (;;){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 offelseP1OUT |= 0x01;// Set P1.0 LED on__bic_SR_register_on_exit(CPUOFF);// Clear CPUOFF bit from 0(SR)
xiaolong wang2：
回复 Ling Zhu2:
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
zengding liu1：
回复 xiaolong wang2:
你好，请问这个问题你是这么解决的？
xiaolong wang2：
回复 zengding liu1:
设置32次采集有问题，设置为16次即可正常解决，我也不知道是怎么回事
xiaolong wang2：
回复 zengding liu1:
/*********************************************************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 16uint 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; } }}
zengding liu1：
回复 xiaolong wang2:
我也这样尝试了，确实是这样的，修改为16次采集一次
