Connecting esp32 with PCF8574

[Eryk]

Hello Renzo, love your post about PCF8574.
I’m doing now a engineer project for my degree and i have a problem. Im using a freenove esp32-wrover-cam(i can post a link to a pinout of this esp32).
Pinout:
https://makeradvisor.com/wp-content/uploads/2023/02/Freenove-ESP32-Wrover-CAM-pinout.jpg

I’m using a cam and wifi on this board, and also i need 7 pins to run other elements (3 buttons, 2 i2c(SDA SLC) for a 64×128 oled display, 1 pin to control POWER LED converter and 1 pin to control transistor controling a small motor). Because of my need of usage a cam and wifi i only left with two ports, 32 and 33, because CAM is disabling all cam ports and wifi is disabling all ACD2 ports. And one of sollutions i found is i2c expander like PCF8574, I managed to emulate i2c on 32 and 33 ports to turn on an display so i thought it would work with expander that way. I bought PCF8574 and i connected it with esp32
esp32 -> pcf8574
vcc -> vcc
GND->GND
32 -> SCL
33-> SDA
I tried to programm a simple code to test a button state read, but it doesn’t work

#include <Wire.h>
#include “PCF8574.h”

// Instantiate Wire for generic use at 400kHz
TwoWire I2Cone = TwoWire(0);
// Instantiate Wire for generic use at 100kHz
TwoWire I2Ctwo = TwoWire(1);

// Set i2c address
PCF8574 pcf8574(&I2Ctwo, 0x20);
//PCF8574 pcf8574(&I2Ctwo, 0x20, 32, 33);
// PCF8574(TwoWire *pWire, uint8_t address, uint8_t interruptPin, void (*interruptFunction)() );
// PCF8574(TwoWire *pWire, uint8_t address, uint8_t sda, uint8_t scl, uint8_t interruptPin, void (*interruptFunction)());

//#define I2C_SDA 33
//#define I2C_SCL 32
//Wire.begin(I2C_SDA, I2C_SCL);

void setup() {
Serial.begin(115200);
// put your setup code here, to run once:
I2Cone.begin(33,32,400000); // SDA pin 33, SCL pin 32, 400kHz frequency

pcf8574.pinMode(P2, INPUT_PULLUP);
pcf8574.begin();
}

void loop() {
// put your main code here, to run repeatedly:
int buttonState = pcf8574.digitalRead(P2);
Serial.println(buttonState);
}

I connecter the bottom with P2 port and it doesn’t work. I don’t know if my esp32 is connecting to this expander or not.

Also another important question, can I emulate a SDA and SCL ports for my display on PCF8574 ports(P0-P7), or i can use other SDA SCL ports on other side of the PCF8574 board? If not then only solluction i have is to use 2 esp32 for this project.

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