我正在运行一个业余项目，但遇到一个问题。我使用带有XC8编译器的MPLABX对图片进行编码。 我正在使用3个模拟输入。它们是AN0，AN1和AN2。代码中也使用了Timer0中断。 当我在AN1和AN2上施加5V电压时，它不会打扰PIC uC，但是当对AN0施加大于3V电压时，Pic会自行复位并保持复位状态，直到电压降至3V以下。
还有其他人遇到这种问题吗？
编辑！
我禁用了定时器中断，并编写了以下代码。 每当向AN0施加5V电压时，仍然会产生相同的问题。
#include <stdio.h>
#include <stdlib.h>
#include <xc.h>
#include <p18f4520.h>
#include "my_header.h"
#define _XTAL_FREQ 20000000 // Fosc frequency for _delay() library
#define green_1 PORTCbits.RC1
#define green_2 PORTCbits.RC2
#define green_3 PORTCbits.RC3
#define green_4 PORTDbits.RD0
#define green_5 PORTDbits.RD1
#define green_6 PORTDbits.RD2
#define green_7 PORTDbits.RD3
#define green_8 PORTCbits.RC4
#define green_9 PORTCbits.RC5
#define green_10 PORTCbits.RC6
void main(){
int kg=0;
//setting the Oscillator Freq. to 125KHz for 8TAd to be 3.2 MicroSeconds
OSCCONbits.IRCF0=0;
OSCCONbits.IRCF1=0;
OSCCONbits.IRCF2=1;
//ADC Module Settings
ADCON1=0b00001100;
ADCON2=0b10010000;
TRISAbits.RA6=0;
TRISAbits.RA7=0;
TRISCbits.RC0=0;
TRISCbits.RC1=0;
TRISCbits.RC2=0;
TRISCbits.RC3=0;
TRISCbits.RC4=0;
TRISCbits.RC5=0;
TRISCbits.RC6=0;
TRISCbits.RC7=0;
TRISDbits.RD0=0;
TRISDbits.RD1=0;
TRISDbits.RD2=0;
TRISDbits.RD3=0;
TRISDbits.RD4=0;
TRISDbits.RD5=0;
TRISDbits.RD6=0;
while(1){
ADCON0=0x00;
ADCON0=0x03;
while(GODONE);
ADON=0;
kg=ADRES;
if (kg >200){
green_1=1;
green_2=0;
green_3=1;
green_4=0;
green_5=0;
green_6=1;
green_7=1;
green_8=0;
green_9=1;
green_10=1;
}
else {
green_1=0;
green_2=0;
green_3=0;
green_4=0;
green_5=0;
green_6=0;
green_7=0;
green_8=0;
green_9=0;
green_10=0;
}
}
}
谢谢大家。
答案 0 :(得分：1)
您似乎正在更改OCCCON寄存器以使用125KHz的系统时钟，但告诉编译器您正在使用20MHz的晶体振荡器。
您尚未发布配置字设置，因此我们无法知道您的系统时钟设置实际上是什么。
无论如何，这就是我设置PIC18F4520的方式：
/*
* File: main.c
* Target: PIC18F4520
* Compiler: XC8 v1.45
* IDE: MPLAB v8.92
*
* PIC18F4520
* +------------:_:------------+
* VPP -> 1 : RE3/MCLR/VPP PGD/RB7 : 40 <> PGD
* AIN(0-5V) -> 2 : RA0/AN0 PGC/RB6 : 39 <> PGC
* <> 3 : RA1 PGM/RB5 : 38 <>
* <> 4 : RA2 RB4 : 37 <>
* <> 5 : RA3 RB3 : 36 <>
* <> 6 : RA4 RB2 : 35 <>
* <> 7 : RA5 RB1 : 34 <>
* <> 8 : RE0 RB0 : 33 <>
* <> 9 : RE1 VDD : 32 <- PWR
* <> 10 : RE2 VSS : 31 <- GND
* PWR -> 11 : VDD RD7 : 30 <>
* GND -> 12 : VSS RD6 : 29 <>
* 20MHZ XTAL -> 13 : RA7/OSC1 RD5 : 28 <>
* 20MHZ XTAL <- 14 : RA6/OSC2 RD4 : 27 <>
* <> 15 : RC0/SOSCO RX/DT/RC7 : 26 <>
* GRN_LED1 <> 16 : RC1/SOSCI TX/CK/RC6 : 25 <> GRN_LED10
* GRN_LED2 <> 17 : RC2/CCP1 SPI_MOSI/RC5 : 24 <> GRN_LED9
* GRN_LED3 <> 18 : RC3/SPI_CLK SPI_MISO/RC4 : 23 <> GRN_LED8
* GRN_LED4 <> 19 : RD0 RD3 : 22 <> GRN_LED7
* GRN_LED5 <> 20 : RD1 RD2 : 21 <> GRN_LED6
* +---------------------------:
* DIP-40
*
*/
#pragma config OSC = HS
#pragma config FCMEN = OFF
#pragma config IESO = OFF
#pragma config BOREN = OFF
#pragma config BORV = 3
#pragma config PWRT = OFF
#pragma config WDTPS = 32768
#pragma config WDT = OFF
#pragma config CCP2MX = PORTC
#pragma config LPT1OSC = ON
#pragma config MCLRE = ON
#pragma config STVREN = ON
#pragma config XINST = OFF
#pragma config LVP = OFF
#pragma config CP0 = OFF, CP1 = OFF, CP2 = OFF, CP3 = OFF
#pragma config CPD = OFF, CPB = OFF
#pragma config WRT0 = OFF, WRT1 = OFF, WRT2 = OFF, WRT3 = OFF
#pragma config WRTD = OFF, WRTB = OFF, WRTC = OFF
#pragma config EBTR0 = OFF, EBTR1 = OFF, EBTR2 = OFF, EBTR3 = OFF
#pragma config EBTRB = OFF
#include <xc.h>
/* Define the frequency we promise to set the clock at */
#define FSYS (20000000L)
#define FCYC (FSYS/4L)
#define _XTAL_FREQ FSYS
/*
* Define the LED output bits
*/
#define green_1 LATCbits.LATC1
#define green_2 LATCbits.LATC2
#define green_3 LATCbits.LATC3
#define green_4 LATDbits.LATD0
#define green_5 LATDbits.LATD1
#define green_6 LATDbits.LATD2
#define green_7 LATDbits.LATD3
#define green_8 LATCbits.LATC4
#define green_9 LATCbits.LATC5
#define green_10 LATCbits.LATC6
/*
* Main program
*/
void main(void)
{
/* declare variable to receive ADC data */
int kg;
/* Disable all interrupt sources */
INTCON = 0;
PIE1 = 0;
PIE2 = 0;
/* Setup the ADC for input on AN0 only */
ADCON0 = 0; /* Disable ADC */
ADCON1 = 0b00001110; /* Set AN0(RA0) as the ADC input */
ADCON2 = 0b10001101; /* Set Right justified data, ACQT as 2 TAD, ADCS as FOSC/16 (20MHz system clock) */
ADCON0bits.ADON = 1; /* Enable ADC */
/* Setup GPIO bits */
TRISCbits.TRISC0=0;
TRISCbits.TRISC1=0;
TRISCbits.TRISC2=0;
TRISCbits.TRISC3=0;
TRISCbits.TRISC4=0;
TRISCbits.TRISC5=0;
TRISCbits.TRISC6=0;
TRISCbits.TRISC7=0;
TRISDbits.TRISD0=0;
TRISDbits.TRISD1=0;
TRISDbits.TRISD2=0;
TRISDbits.TRISD3=0;
TRISDbits.TRISD4=0;
TRISDbits.TRISD5=0;
TRISDbits.TRISD6=0;
/*
* Application loop
*/
ADCON0bits.GO = 1; /* Start first ADC conversion */
for(;;)
{
if(ADCON0bits.GO == 0)
{
/* Save value of ADC conversion */
kg = ADRESL;
kg |= (int)(ADRESH)<<8;
/* Start next ADC conversion */
ADCON0bits.GO = 1;
/* show results in the LEDs */
if (kg >200){
green_1=1;
green_2=0;
green_3=1;
green_4=0;
green_5=0;
green_6=1;
green_7=1;
green_8=0;
green_9=1;
green_10=1;
}
else {
green_1=0;
green_2=0;
green_3=0;
green_4=0;
green_5=0;
green_6=0;
green_7=0;
green_8=0;
green_9=0;
green_10=0;
}
}
}
}