ESP32 timerISR in separate header but can't delare variable

Projects Programming
1

Hi,

I wanted to treat the timer ISR from my ESP32 as a separate module. So I wanted to put the ISR declaration in a header file. Now I want to increase the variable count every time the timer gives an interrupt. But when building the project the compiler gives the error count not declared in this scope. I already tried declaring it with "extern" but the error remains.
Can someone help me get on the right track?

Here is the code:

timersettings.h

/*-----------------------------------------------------------------------------------------------
timersettings.h
-----------------------------------------------------------------------------------------------*/

#ifndef timersettings_h
#define timersettings_h
#endif

#include <Arduino.h>

#define HALF_SEC    (count*50)
extern int count;

// --------------- Setup Timer1:
hw_timer_t *timer1 = NULL;
hw_timer_t *timer2 = NULL;

void IRAM_ATTR onTimer1ISR();

void IRAM_ATTR onTimer2ISR();

timersettings.c

#include <timersettings.h>

unsigned int timer1Flag, timer2Flag;

void IRAM_ATTR onTimer1ISR()
{
  // What to do when the timer ticks out.
  timer1Flag = 1;
  count++;
}

void IRAM_ATTR onTimer2ISR()
{
  // What to do when the timer ticks out.
  timer2Flag = 1;
}

and the main.c

#include <Arduino.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <Wire.h>
#include <SPI.h>
#include "Adafruit_PWMServoDriver.h"
#include <joysticks.h>
#include <timersettings.h>

unsigned long buttonTime = 0, prevButtonTime = 0, startTime = 0;
unsigned int prevState, curState = 0;
unsigned int buttonFlag = 0;
unsigned int freq = 0;
unsigned int buttonState;
extern int count = 0;



// --------------- Setup Button Interrupt
void IRAM_ATTR isrButton() 
{
  buttonTime = millis();
  if (buttonTime - prevButtonTime > 50)
  {
    prevButtonTime = buttonTime;
    curState = 1;
  }
  
}

void setup() 
{
  //startTime = millis();
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println("Serial Port Initialised");

  freq = getCpuFrequencyMhz();
  Serial.printf("CPU FREQ: %dMHz \n",freq);
  freq = getApbFrequency();
  Serial.printf("APB FREQ: %dMHz \n",(freq/1000000));
  

  // hardware interrupt init
  pinMode(JOY_LEFT_BUT, INPUT_PULLDOWN);
  attachInterrupt(JOY_LEFT_BUT, isrButton, ONHIGH);
  

  // timer1 init
  timer1 = timerBegin(0, 80, true);    // timer0 (from 0 to 3), 80 prescaler(80MHZ/PRESCALER), counting up (true, down=false)
  timerAttachInterrupt(timer1, &onTimer1ISR, false);   // attach ISR to timer  (true edge triggered, false level triggered)
  timerAlarmWrite(timer1, 10000, true);    // Set countvalue to 10 milliseconds autoreload(true)
  timerAlarmEnable(timer1);   // Enable timer
  
}

void loop() 
{
  // put your main code here, to run repeatedly:


  joystick joystickL;
  joystickL.curButState = false;
  joystickL.prevButState = false;

  // button state logic
  if( (curState == 1) && (prevState == 0) )     // button is pressed
  {

    if( (curState == 1) && (count >= 50 ) )    // button is held for at least 0.5 seconds
    {
      buttonState = HELD;
    }
    
  }
  else if( (curState ==1) && (count < 0) )    // button is pushed but not held
    {
      buttonState = PRESSED;
    }
  else if( (curState == 0) && (prevState == 1) )// button is released
  {
    buttonState = RELEASED;
  }
  else
  {
    buttonState = INITIAL;
  }
  // end button state logic

  switch (buttonState)
  {
  case PRESSED:
    Serial.printf("Button: %s\n",buttonState);
    prevState = curState;
    break;

  case RELEASED:
    Serial.printf("Button: %s\n",buttonState);
    prevState = curState;
    break;

  case HELD:
    Serial.printf("Button: %s\n",buttonState);

    break;
  
  default:
    curState = 0;
    prevState = 0;
    break;
  }

}

I'm still debugging the rest of the program so don't mind the buttons etc. I just need to know how to solve this:

Processing esp32doit-devkit-v1 (platform: espressif32; board: esp32doit-devkit-v1; framework: arduino)
----------------------------------------------------------------------------------------------------------------Verbose mode can be enabled via `-v, --verbose` option
CONFIGURATION: https://docs.platformio.org/page/boards/espressif32/esp32doit-devkit-v1.html
PLATFORM: Espressif 32 (6.6.0) > DOIT ESP32 DEVKIT V1
HARDWARE: ESP32 240MHz, 320KB RAM, 4MB Flash
DEBUG: Current (cmsis-dap) External (cmsis-dap, esp-bridge, esp-prog, iot-bus-jtag, jlink, minimodule, olimex-arm-usb-ocd, olimex-arm-usb-ocd-h, olimex-arm-usb-tiny-h, olimex-jtag-tiny, tumpa)
PACKAGES:
 - framework-arduinoespressif32 @ 3.20014.231204 (2.0.14)
 - tool-esptoolpy @ 1.40501.0 (4.5.1)
 - toolchain-xtensa-esp32 @ 8.4.0+2021r2-patch5
LDF: Library Dependency Finder -> https://bit.ly/configure-pio-ldf
LDF Modes: Finder ~ chain, Compatibility ~ soft
Found 36 compatible libraries
Scanning dependencies...
Dependency Graph
|-- Adafruit PWM Servo Driver Library @ 3.0.2
|-- SPI @ 2.0.0
|-- Wire @ 2.0.0
Building in release mode
Compiling .pio\build\esp32doit-devkit-v1\src\main.cpp.o
Compiling .pio\build\esp32doit-devkit-v1\src\timersettings.c.o
src/main.cpp:20:12: warning: 'count' initialized and declared 'extern'
 extern int count = 0;
            ^~~~~
Linking .pio\build\esp32doit-devkit-v1\firmware.elf
c:/users/td/.platformio/packages/toolchain-xtensa-esp32@8.4.0+2021r2-patch5/bin/../lib/gcc/xtensa-esp32-elf/8.4.0/../../../../xtensa-esp32-elf/bin/ld.exe: .pio\build\esp32doit-devkit-v1\src\timersettings.c.o:C:\Users\TD\Documents\PlatformIO\Projects\Remote/include/timersettings.h:16: multiple definition of `timer2'; .pio\build\esp32doit-devkit-v1\src\main.cpp.o:C:\Users\TD\Documents\PlatformIO\Projects\Remote/include/timersettings.h:16: first defined here
c:/users/td/.platformio/packages/toolchain-xtensa-esp32@8.4.0+2021r2-patch5/bin/../lib/gcc/xtensa-esp32-elf/8.4.0/../../../../xtensa-esp32-elf/bin/ld.exe: .pio\build\esp32doit-devkit-v1\src\timersettings.c.o:C:\Users\TD\Documents\PlatformIO\Projects\Remote/include/timersettings.h:15: multiple definition of `timer1'; .pio\build\esp32doit-devkit-v1\src\main.cpp.o:C:\Users\TD\Documents\PlatformIO\Projects\Remote/include/timersettings.h:15: first defined here
c:/users/td/.platformio/packages/toolchain-xtensa-esp32@8.4.0+2021r2-patch5/bin/../lib/gcc/xtensa-esp32-elf/8.4.0/../../../../xtensa-esp32-elf/bin/ld.exe: .pio\build\esp32doit-devkit-v1\src\main.cpp.o:(.literal._Z5setupv+0x2c): undefined reference to `onTimer1ISR()'
collect2.exe: error: ld returned 1 exit status
*** [.pio\build\esp32doit-devkit-v1\firmware.elf] Error 1
========================================= [FAILED] Took 20.44 seconds =========================================
2

you appear to have declared

extern int count;

in timersettings.h and main.c but where do you define count? e.g.

int count=0;

should be in timersettings.c ???

extern declarations only declare a variable exists somewhere - but you have define it (create it) somewhere

also you cannot initialize in an declaration

extern int count = 0;

only in a definition

3

I had tried a few different notations of it. It seems that this way made most of the error go away.

But it still won't let me build the project. Can i split up the declaration and definition of the ISR this way? Because when I put all of it in the main.c file it does let me build it.

4

Post your latest, complete code with the "different notations" that you tried. Post the complete error messages.

5

note if the header files are in the directory with the .ino file use "" not <> which is for system header files)
if I compile and run multi_file_1.ino

#include <Arduino.h>
#include "timersettings.h"

void setup() {
  Serial.begin(115200);
  delay(2000);
  Serial.println(count);
  onTimer1ISR();
  Serial.println(count);
  }

void loop() {}

timersettings.cpp

#include "timersettings.h"

unsigned int timer1Flag, timer2Flag;

int count=0;   // define count

void IRAM_ATTR onTimer1ISR()
{
  // What to do when the timer ticks out.
  timer1Flag = 1;
  count++;
}

timersettings.h

#ifndef timersettings_h
#define timersettings_h

#include <Arduino.h>

#define HALF_SEC    (count*50)
extern int count;    // declare count

void IRAM_ATTR onTimer1ISR();

void IRAM_ATTR onTimer2ISR();

#endif

a run displays

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the directory contains

image
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