PIC16F1575 LED 闪烁问题

Question

我是 PIC 编程的新手，我正在努力在程序中设置振荡器，如果有人能帮助我解释我做错了什么，我将不胜感激。

// PIC16F1575 Configuration Bit Settings

// 'C' source line config statements

// CONFIG1
#pragma config FOSC = INTOSC    // Oscillator Selection Bits (INTOSC oscillator; I/O functio
#pragma config WDTE = OFF       // Watchdog Timer Enable (WDT disabled)
#pragma config PWRTE = ON       // Power-up Timer Enable (PWRT enabled)
#pragma config MCLRE = ON       // MCLR Pin Function Select (MCLR/VPP pin function is MCLR)
#pragma config CP = ON          // Flash Program Memory Code Protection (Program memory code
#pragma config BOREN = OFF      // Brown-out Reset Enable (Brown-out Reset disabled)
#pragma config CLKOUTEN = ON    // Clock Out Enable (CLKOUT function is enabled on the CLKOU

// CONFIG2
#pragma config WRT = OFF        // Flash Memory Self-Write Protection (Write protection off)
#pragma config PPS1WAY = ON     // PPSLOCK bit One-Way Set Enable bit (PPSLOCKED Bit Can Be 
#pragma config PLLEN = ON      // PLL Enable (4x PLL disabled)
#pragma config STVREN = ON      // Stack Overflow/Underflow Reset Enable (Stack Overflow or 
#pragma config BORV = LO        // Brown-out Reset Voltage Selection (Brown-out Reset Voltag
#pragma config LPBOREN = OFF    // Low Power Brown-out Reset enable bit (LPBOR is disabled)
#pragma config DEBUG = OFF      // In-Circuit Debugger Mode (In-Circuit Debugger disabled, I
#pragma config LVP = ON         // Low-Voltage Programming Enable (Low-voltage programming e

// #pragma config statements should precede project file includes.
// Use project enums instead of #define for ON and OFF.

#include <xc.h>
-----------------------------------------------

#include "config.h"
#include <xc.h>

//configuring which oscillator to use (target 64MHz)

#define _XTAL_FREQ 64000000

void main(void) {
    
    OSCCONbits.IRCF = 0b1111; //sets internal oscillator speed to 16MHz
    OSCCONbits.SPLLEN = 0b1; //sets prescaler to x4 making signal 64MHz 
    OSCCONbits.SCS = 0b00;    //sets system clock to fosc setting
    
    //below is a blinking LED test to make sure oscillator configured correctly
    
    //sets RA2 to digital output
    ANSELAbits.ANSA2 = 0; //removes analogue out to led
    TRISAbits.TRISA2 = 0; //sets RA0 to output
            
    //blinks LED on output
            while(1){
                LATAbits.LATA2 = 1;
                __delay_ms(1000);
                LATAbits.LATA2 = 0;
                __delay_ms(1000);
            }
    return;
}

我以为我已经正确设置了所有内容，之前 LED 灯可以正常工作，但现在它似乎不再工作了。

Answer 1

看起来您正在尝试将时钟速度设置为 64Mhz，这对于该设备来说根本不可能，因为最大时钟速度为 32Mhz。看看时钟图：

您可以看到，将

PLLEN

设置为

ON

并将

FOSC

设置为

INTOSC

，您正在将

INTOSC

信号运行到 PLL 中。与：

OSCCONbits.IRCF = 0b1111; //sets internal oscillator speed to 16MHz

将 16 Mhz 运行到 4x PLL 中以获得 64Mhz，这太快了。该设备的最大时钟速度为 32Mhz。为了获得 32Mhz，请将

IRCF

设置为

0b1110

以在

INTOSC

上获得 8Mhz（如数据表所述）：

bit 6-3 IRCF<3:0>: Internal Oscillator Frequency Select bits
1111 = 16 MHz HF
1110 = 8 MHz or 32 MHz HF (see Section 5.2.2.1 “HFINTOSC”)
1101 = 4 MHz HF
1100 = 2 MHz HF
1011 = 1 MHz HF
1010 = 500 kHz HF(1)
1001 = 250 kHz HF(1)
1000 = 125 kHz HF(1)
0111 = 500 kHz MF (default upon Reset)
0110 = 250 kHz MF
0101 = 125 kHz MF
0100 = 62.5 kHz MF
0011 = 31.25 kHz HF(1)
0010 = 31.25 kHz MF
000x = 31 kHz LF

另一个选项是设置：

OSCCONbits.SCS = 0b10;

直接使用

INTOSC

信号。通过将

SCS

设置为

0b1111

，使用此方法可以获得的最大速度将为 16Mhz。

注意

确保根据您的决定更新

_XTAL_FREQ

。