尝试在arduino中声明常量时遇到问题

编程问答 2022-06-08

问题描述

我正在为arduino制作一个相当简单的声音脚本。这是我的脚本：

#include <digitalWriteFast.h>

struct AudioHandler {
  //Alter these as you require
  const int pin = 2;
  float frequency = 1;
  float dutyCycle = 1;
    
  //These are internal variables that you shouldn't touch
  unsigned long prevMicros = 0;
  bool onHalf = true;  //This just asks which half of the wave the sound is on
  
  //This just checks the time and asks if it should switch to the other half of the wave
  void updateSound() {
    if ((micros() - prevMicros > (1000000 / frequency) * dutyCycle) && (onHalf)) {
      prevMicros = micros();
      onHalf = false;
      
      digitalWriteFast(pin,false);
    } else if ((micros() - prevMicros > (1000000 / frequency) * (1 - dutyCycle)) && (!onHalf)) {
      prevMicros = micros();
      onHalf = true;
      
      digitalWriteFast(pin,true);
    }
  }
};

AudioHandler test_1;
AudioHandler test_2;
AudioHandler test_3;
AudioHandler test_4;

void setup() {
  pinModeFast(3,OUTPUT); test_1.frequency = 65.41; test_1.dutyCycle = 0.5;
  pinModeFast(4,OUTPUT); test_2.frequency = 82.41; test_2.dutyCycle = 0.5;
  pinModeFast(5,OUTPUT); test_3.frequency = 98.00; test_3.dutyCycle = 0.5;
  pinModeFast(6,OUTPUT); test_4.frequency = 130.81; test_4.dutyCycle = 0.5;

  //I need to set the pin,but couldn't figure out how to do it in struct declaration
  //Also,this 
  int *pinPointer_1; pinPointer_1 = &test_1.pin; *pinPointer_1 = 3;
  int *pinPointer_2; pinPointer_2 = &test_2.pin; *pinPointer_2 = 4;
  int *pinPointer_3; pinPointer_3 = &test_3.pin; *pinPointer_3 = 5;
  int *pinPointer_4; pinPointer_4 = &test_4.pin; *pinPointer_4 = 6;
}

void loop() {
  test_1.updateSound();
  test_2.updateSound();
  test_3.updateSound();
  test_4.updateSound();
}

实际上，我的脚本应该可以正常工作，但是arduino IDE抱怨：

Warning: Board breadboard:avr:atmega328bb doesn't define a 'build.board' preference. Auto-set to: AVR_ATMEGA328BB
C:\Users\aj200\Documents\GitHub\My-Projects\My-Projects\Active Projects\Sound_PWM_Help\Sound_PWM_Help.ino: In member function 'updateSound':

Sound_PWM_Help:19:7: error: call to 'NonConstantUsed' declared with attribute error: 

       digitalWriteFast(pin,false);

       ^

Sound_PWM_Help:24:7: error: call to 'NonConstantUsed' declared with attribute error: 

       digitalWriteFast(pin,true);

       ^

lto-wrapper.exe: fatal error: C:\Program Files (x86)\Arduino\hardware\tools\avr/bin/avr-gcc returned 1 exit status

compilation terminated.

c:/program files (x86)/arduino/hardware/tools/avr/bin/../lib/gcc/avr/7.3.0/../../../../avr/bin/ld.exe: error: lto-wrapper failed

collect2.exe: error: ld returned 1 exit status

exit status 1
call to 'NonConstantUsed' declared with attribute error:

从理论上讲，这应该是完整且实用的。但是，由于某种原因，arduino编译器会说变量“ pin”不是常数（烦人的digitalWriteFast（pin，state）需要常数）。我在这里想念什么？

先谢谢您， 安德烈

解决方法

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arduinoarduino-c++constants