如何在 MICROCHIP XC8 的库中正确使用 __delay_ms()？答案

【问题标题】：How to properly use __delay_ms() in libraries in MICROCHIP XC8?如何在 MICROCHIP XC8 的库中正确使用 __delay_ms()？
【发布时间】：2021-02-06 04:30:02
【问题描述】：

我在尝试创建一个在函数内调用“__delay_ms()”的库时遇到了一些麻烦。进行了广泛的搜索，但找不到解决方案，也没有其他解释。我正在使用 XC8 v2.30 MPLAB 5.45。

我有一个包含标题“qc3.h”的主函数：

#include <xc.h> // include standard header file

// set Config bits
#pragma config FOSC=INTOSC, PLLEN=OFF, WDTE=OFF, MCLRE=ON,
#pragma config CLKOUTEN=OFF, IESO=OFF, FCMEN=OFF,CP=OFF, CPD=OFF,BOREN=OFF
#pragma config WRT=OFF,STVREN=ON,BORV=LO,LVP=OFF

// Definitions
#define _XTAL_FREQ 500000 // this is used by the __delay_ms(xx) and __delay_us(xx) functions

#include "qc3.h"

#define LED PORTAbits.RA2




//**********************************************************************************
//***************** main routine ***********************************************
//**********************************************************************************
void main ( ) 
{
    // set up oscillator control register
    OSCCONbits.SPLLEN=0; // PLL is disabled
    OSCCONbits.IRCF=0x07; //set OSCCON IRCF bits to select OSC frequency=500Khz
    OSCCONbits.SCS=0x02; //set the SCS bits to select internal oscillator block
    // OSCON should be 0x7Ah now.

    // Set up I/O pins
    ANSELAbits.ANSELA=0; // set all analog pins to digital I/O
    ADCON0bits.ADON=0; // turn ADC off
    DACCON0bits.DACEN=0; // turn DAC off

    // PORT A Assignments (0 = OUTPUT, 1 = INPUT)
    TRISAbits.TRISA0 = 0; // RA0 = nc
    TRISAbits.TRISA1 = 0; // RA1 = nc
    TRISAbits.TRISA2 = 0; // RA2 = nc
    TRISAbits.TRISA3 = 0; // RA3 = nc (MCLR)
    TRISAbits.TRISA4 = 0; // RA4 = nc
    TRISAbits.TRISA5 = 0; // RA5 = nc
    
    
    QC3_Initialize(); // incia protocolo para handshake
         
    while(1)
    {
        __delay_ms(100);
        LED = 1;
        __delay_ms(100);
        LED = 0; 
    } 
}

qc3.h：

#ifndef QC3_H_ /* Include guard */
#define QC3_H_

/**
  Section: Included Files
*/

#include <xc.h>
#include <stdint.h>
#include <stdbool.h>

#ifdef __cplusplus // Provide C++ Compatibility

    extern "C" {

#endif

//Quick Charge 3 Pin defines
#define DP_HIGH PORTAbits.RA0
#define DM_HIGH PORTAbits.RA1

#define DP_LOW PORTAbits.RA5
#define DM_LOW PORTAbits.RA4

void QC3_Initialize(void);

//void onewireWriteBit(int b);
//unsigned char onewireReadBit();
//unsigned char onewireInit();
//unsigned char onewireReadByte();
//void onewireWriteByte(char data);
//unsigned char onewireCRC(unsigned char* addr, unsigned char len);

#ifdef __cplusplus // Provide C++ Compatibility

    }

#endif

#endif

qc3.c:

#include "qc3.h"


void QC3_Initialize(void) {
  __delay_ms(150);
 DP_HIGH = 0;
  
}

错误：

make -f nbproject/Makefile-default.mk SUBPROJECTS= .build-conf
make[1]: Entering directory 'D:/Google Drive/Projetos/Pedais/Fonte para pedais isolada/QUICK CHARGE/PIC'
make -f nbproject/Makefile-default.mk dist/default/production/PIC.production.hex
make[2]: Entering directory 'D:/Google Drive/Projetos/Pedais/Fonte para pedais isolada/QUICK CHARGE/PIC'
"D:\Program Files\Microchip\xc8\v2.30\bin\xc8-cc.exe" -mcpu=12F1840 -c -mdfp="D:/Program Files/Microchip/MPLABX/v5.45/packs/Microchip/PIC12-16F1xxx_DFP/1.2.63/xc8" -fno-short-double -fno-short-float -O0 -fasmfile -maddrqual=ignore -xassembler-with-cpp -I"head_and_lib" -mwarn=-3 -Wa,-a -DXPRJ_default=default -msummary=-psect,-class,+mem,-hex,-file -ginhx032 -Wl,--data-init -mno-keep-startup -mno-osccal -mno-resetbits -mno-save-resetbits -mno-download -mno-stackcall -std=c99 -gdwarf-3 -mstack=compiled:auto:auto -o build/default/production/head_and_lib/qc3.p1 head_and_lib/qc3.c 
"D:\Program Files\Microchip\xc8\v2.30\bin\xc8-cc.exe" -mcpu=12F1840 -c -mdfp="D:/Program Files/Microchip/MPLABX/v5.45/packs/Microchip/PIC12-16F1xxx_DFP/1.2.63/xc8" -fno-short-double -fno-short-float -O0 -fasmfile -maddrqual=ignore -xassembler-with-cpp -I"head_and_lib" -mwarn=-3 -Wa,-a -DXPRJ_default=default -msummary=-psect,-class,+mem,-hex,-file -ginhx032 -Wl,--data-init -mno-keep-startup -mno-osccal -mno-resetbits -mno-save-resetbits -mno-download -mno-stackcall -std=c99 -gdwarf-3 -mstack=compiled:auto:auto -o build/default/production/source/ISOPOWER.p1 source/ISOPOWER.c 
make[2]: *** [build/default/production/head_and_lib/qc3.p1] Error 1
make[2]: *** Waiting for unfinished jobs....
head_and_lib/qc3.c:6:3: error: use of undeclared identifier '_XTAL_FREQ'
  __delay_ms(150);
  ^
D:/Program Files/Microchip/MPLABX/v5.45/packs/Microchip/PIC12-16F1xxx_DFP/1.2.63/xc8\pic\include\pic.h:101:51: note: expanded from macro '__delay_ms'
#define __delay_ms(x) _delay((unsigned long)((x)*(_XTAL_FREQ/4000.0)))
                                                  ^
1 error generated.
(908) exit status = 1
nbproject/Makefile-default.mk:123: recipe for target 'build/default/production/head_and_lib/qc3.p1' failed
make[1]: *** [.build-conf] Error 2
make: *** [.build-impl] Error 2
make[2]: Leaving directory 'D:/Google Drive/Projetos/Pedais/Fonte para pedais isolada/QUICK CHARGE/PIC'
nbproject/Makefile-default.mk:91: recipe for target '.build-conf' failed
make[1]: Leaving directory 'D:/Google Drive/Projetos/Pedais/Fonte para pedais isolada/QUICK CHARGE/PIC'
nbproject/Makefile-impl.mk:39: recipe for target '.build-impl' failed

BUILD FAILED (exit value 2, total time: 913ms)

编译器报错（使用了未声明的标识符“_XTAL_FREQ”），但在#define _XTAL_FREQ 500000 之后声明的标头。为什么？

如果我去掉函数的延迟：

void QC3_Initialize(void) {
  __delay_ms(150);
 DP_HIGH = 0;

编译成功

所以。如果从未声明过 QC3.c（即使在“.h”标头中），“何时”“调用”它？

如果“.c”包含“.h”，为什么我应该声明“.h”？不应该反过来吗？或者至少是“.h” 包含“.c”？

看似基本的东西，但它让我大吃一惊

谢谢

【问题讨论】：

如果问题尚未解决：您必须在包含“xc.h”头文件之前声明“#define _XTAL_FREQ 500000”。因为 __delay_ms() 宏使用了 xc.h 头文件中的 _XTAL_FREQ 定义。

标签： c pic microchip mplab xc8

【解决方案1】：

您必须在 .c 文件中提供 _XTAL_FREQ 才能获得。

【讨论】：

【解决方案2】：

您在包含main() 的C 源文件中定义_XTAL_FREQ，但是，由于您在qc3.c（一个单独翻译单元）中调用__delay_ms()，那就是该定义需要存在的地方。

最简单的修复方法可能是在qc3.h 中定义它。

【讨论】：