[mark estrada]

Hello

Hey,
Let me try with a devkit, may I know if the wiring you are saying is the link above?
Cathode is connected to the P0-P17 of the PCF8575 and the anode is connected to the Arduino pins.

Which is quite different from the GitHub page image

I am using the module type and not the IC Type so there is no other external connection like a resistor because your YouTube video has a resistor connected to some pins.

* PCF8575 —– esp32
* GND —– GND
* VCC —– 3.3V
* SDA —– 21
* SCL —– 22

Thank you!

[mark estrada]

Hi,
Can you tell me what is the mistake on the wiring or power supply to the LEDs?

The README.MD files of your library and on your site are different also so what is the correct wiring?

Also, this is my ESP32 board that I have purchased https://www.aliexpress.com/item/1005004180608116.html

Maybe the original poster and I have the same board.

Thanks and more power!

[mark estrada]

Tried it on both my 30 pins and 38 pins ESP32.

They both detected the I2C device at the default address of 0x20 but even the basic blink led of this library does not work.

I have tried switching the connection of the P0 on the PCF from anode to cathode but it does not work also.
If the anode is connected to P0 and the cathode is to ground, the LED lights up but it does not blink.
If the cathode is connected to P0 and the anode is to 3.3V, the LED does not light up.

I tried connecting a normal I2C LCD to the SCL/SDA pins and it was successful.

Not sure what is missing but maybe some compatibility problem with my ESP32.

The original poster of this post has the same issue. I guess I am encountering the same.

[mark estrada]

I2C Scanner is okay though as that is the first thing I have tested.

Scanning... 
I2C device found at address 0x20!
done
 
Scanning... 
I2C device found at address 0x20! 
done

But the LED does not blink. I changed the pins to the different output ports of PFC8575 but I am not successful as well.

#include "Arduino.h"
#include "PCF8575.h"

// Set i2c address
PCF8575 pcf8575(0x20);

const int PIN = P7;
void setup()
{
  Serial.begin(9600);

  // Set pinMode to OUTPUT
  pcf8575.pinMode(PIN, OUTPUT);
  pcf8575.begin();
  pcf8575.digitalWrite(PIN, HIGH);
}

void loop()
{
  Serial.println("HIGH");
  pcf8575.digitalWrite(PIN, LOW);
  delay(2000);
  Serial.println("LOW");
  pcf8575.digitalWrite(PIN, HIGH);
  delay(2000);
}

In this video of yours, I notice a resistor there where is it connected? https://www.youtube.com/watch?v=jWeHzBLeN6s

[mark estrada]

Hello,
Not sure why but I have tried this library with a NodeMCU ESP32s and the PCF8575 module.

Even the simple blink program does not work.

Followed

* PCF8575 —– esp32
* GND —– GND
* VCC —– 3.3V
* SDA —– 21
* SCL —– 22

LED Cathode is connected to PCF8575 P0 and Anode is connected to
3.3 V of ESP32

Is there something wrong with my setup?

[Author]

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