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我按照本教程更改了我的微控制器 16f1827 的代码。我还更改了代码的功能。如果 ADC 值超过最大值的一半，它应该打开一个 LED。ADC 值，如果小于一半，则关闭 LED。

// CONFIG
#pragma config FOSC = HS      // Oscillator Selection bits (HS oscillator)
#pragma config WDTE = OFF     // Watchdog Timer Enable bit (WDT disabled)
#pragma config PWRTE = OFF    // Power-up Timer Enable bit (PWRT disabled)
#pragma config BOREN = OFF    // Brown-out Reset Enable bit (BOR disabled)
#pragma config LVP = OFF      // Low-Voltage (Single-Supply) In-Circuit Serial Programming Enable bit (RB3 is digital I/O, HV on MCLR must be used for programming)
#pragma config CPD = OFF      // Data EEPROM Memory Code Protection bit (Data EEPROM code protection off)
#pragma config WRT = OFF      // Flash Program Memory Write Enable bits (Write protection off; all program memory may be written to by EECON control)
#pragma config CP = OFF       // Flash Program Memory Code Protection bit (Code protection off)

#include <xc.h>
#include <pic16f1827.h>

#define _XTAL_FREQ 8000000

void ADC_Init()
{
  ADCON0 = 0x81;               //Turn ON ADC and Clock Selection
  ADCON1 = 0x00;               //All pins as Analog Input and setting Reference Voltages
}

unsigned int ADC_Read(unsigned char channel)
{
  if(channel > 7)              //Channel range is 0 ~ 7
    return 0;

  ADCON0 &= 0xC5;              //Clearing channel selection bits
  ADCON0 |= channel<<3;        //Setting channel selection bits
  __delay_ms(2);               //Acquisition time to charge hold capacitor
  GO_nDONE = 1;                //Initializes A/D conversion
  while(GO_nDONE);             //Waiting for conversion to complete
  return ((ADRESH<<8)+ADRESL); //Return result
}

void main()
{
  unsigned int a;
  TRISA = 0xFF;                 //Analog pins as Input
  TRISB = 0x00;                 //Port B as Output
  //TRISC = 0x00;                 //Port C as Output
  ADC_Init();                   //Initialize ADC

  do
  {
    a = ADC_Read(0);            //Read Analog Channel 0
    //PORTB = a;                  //Write Lower bits to PORTB
    //PORTC = a>>8;               //Write Higher 2 bits to PORTC


if(a > 512){
PORTBbits.RB7 = 1;
}else{
PORTBbits.RB7 = 0;
}


    __delay_ms(100);            //Delay
  }while(1);                    //Infinite Loop
}

代码在 XC8 中编译没有错误。问题是 PIC 检测到 ADC 变化太慢。如果我将输入引脚连接到正参考值，它会以大约 2 秒的延迟打开 LED。当我将 ADC 输入更改为 0v 时也会发生同样的情况。检测到所有变化都非常缓慢。为什么ADC工作这么慢？

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1 回答 1

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您链接到的教程使用带有 8MHz 晶体振荡器的 PIC16F877A，而您似乎正在尝试使用带有内部振荡器而不是外部振荡器的 PIC16F1827。像您所做的那样仅更改 PIC 头文件是不够的。您还必须设置所需的振荡器模式并注意两个部分之间不同的任何其他配置选项。我不确定，但我认为 16F1827 的默认内部振荡器频率是 1MHz，而不是 8MHz。这可能有助于解释您遇到的问题。

顺便说一句：不要试图捏造你的代码。确保正确配置微控制器，否则它们迟早会咬你一口。

于 2016-09-02T16:05:38.023 回答