GPIO0 (D3) not allow analogWrite - ESP8266 NodeMCU Dev. Kit

Need Help With My Project
1

Hi Blynkers,

I have a very weird issue when I migrated my sketch to Blynk 2.0.

The code is a 4 channel led lamp, where with the PWM output trought the GPIO I can control the brightness of the leds.

This piece of code was working fine with the legacy Blynk, but with the new Blynk it looks like I can’t set the PWM output to GPIO0, but the other outputs works.

The code is too long, the I’ll show the main parts related to the fail:

//Declarations
#define BLYNK_TEMPLATE_ID "--------------------------"
#define BLYNK_DEVICE_NAME "Lampara SunnyReef"

#define BLYNK_FIRMWARE_VERSION        "0.2.0"

#define BLYNK_PRINT Serial
//#define BLYNK_DEBUG

#define APP_DEBUG

// Uncomment your board, or configure a custom board in Settings.h
//#define USE_SPARKFUN_BLYNK_BOARD
#define USE_NODE_MCU_BOARD
//#define USE_WITTY_CLOUD_BOARD
//#define USE_WEMOS_D1_MINI

#include "BlynkEdgent.h"


#include <TimeLib.h>
#include <SoftwareSerial.h>
#include <SimpleTimer.h>
#include <WidgetRTC.h>

int PWM_Digital_Canal[5] = { 16, 5, 4, 0, 2};

void setup()
{
  Serial.begin(115200); // See the connection status in Serial Monitor
  setSyncInterval(1);
  rtc.begin();

  Serial.println("Iniciando App");
  //Inicializa el controlador y sus variables
  analogWriteFreq(250);
  int i;
  for (i = 0; i < 4; i = i + 1)
  {
    pinMode(PWM_Digital_Canal[i], OUTPUT);
    analogWrite(PWM_Digital_Canal[i], potCanal[i]*proteccion_temp / 100);
  }
  pinMode(Relay, OUTPUT);

 BlynkEdgent.begin();
 
  actualizaLuzTemp();
  timer.setInterval(60000, actualizaLuzTemp);
  timer.setInterval(5000, leeTemperatura);
  setSyncInterval(10 * 60); // Sync interval in seconds (10 minutes)
}

void actualizaLuzTemp()
{
/* a lot of code not related with the fail */
int i;
  for (i = 0; i < 4; i = i + 1 )
  {
    analogWrite(PWM_Digital_Canal[i], potCanal[i]*proteccion_temp / 100); 
    luz_anterior[i] = potCanal[i];
    delay(10);
  }
  Blynk.virtualWrite(Virtual_Total_Azul, (potCanal[0] + potCanal[1] + potCanal[3]+ potCanal[2]*3/5)*proteccion_temp / 100);
  Blynk.virtualWrite(Virtual_Azul_Blanco, (potCanal[2])*2/5*proteccion_temp / 100);

  terminal.println(currentTime);

  Blynk.virtualWrite(GraphTemp_LED, temp_LED);

  terminal.println("LED " + String( temp_LED) + "°C ");

  terminal.println(Modo_txt[Modo]);
  for (i = 0; i < 4; i = i + 1 )
  {
    terminal.print("Canal ");
    terminal.print(String(i + 1));
    terminal.print(": ");
    terminal.print(String(potCanal[i]*proteccion_temp / 100));
    if ( Luz_Luna && ( potCanal[i] <= 10 ) && ( ( i == 0) || ( i == 3))) terminal.print(" Luna");
    terminal.println("");
  }
  terminal.println(F("-----------------"));
  terminal.flush();
}

The line:
analogWrite(PWM_Digital_Canal[i], potCanal[i]*proteccion_temp / 100);
does not work for GPIO0 only.
I’m using the last Arduino IDE, with all the upgraded libraries.

I know the code is doing right because I cann see at the Blynk app the messages in the terminal widget with the rigth values for each GPIO (channel).

Any ideas?

2

I highly recommend you to read this article

3

Thank for your advice, I already readed all about the GPIO used at the boot, But this code was working with the legacy Blynk.

For my lamp, the GPIO0 just produce a litlle flash at the boot with the old version of Blynk.

Any other ideas?

4

Look at the Settings.h tab of the sketch.
You’ll see that GPIO0 is already in use.

Pete.

5

Thanks Pete. As usual you are a great help.

Can I comment this line at Settings.h

#define BOARD_BUTTON_PIN 0

?

6

Not really. You can change to a different GPIO, or preferably start using a different GPIO for your PWM.
If you don’t have any spare GPIOs then stop using Edgent.

Pete.

7

or get a different board, the esp32 has more pins.

8

Thanks Pete,

Fortunatelly, on this project I have spares GPIO.

It worked now!