Problem I2C @ ESP32-CAM and setup PCF8574A

[MAWMN]

/************************************************/
/***** I2C library for PCF8574 (XREEF)      *****/
/***** I2C chip = PCA8574A – addr 0x38       *****/
/***** with A0=x, A1=x, A2=x (x= GND)        *****/
/************************************************/
/***** ESP32-CAM I2C bus uses pins:          *****/
/***** GPIO15 = SCL (ESP32_CAM)              *****/
/***** GPIO14 = SDA (ESP32_CAM)              *****/
/************************************************/

Problem I2C @ ESP32-CAM (AI Thinker Board)
cpp

#include <Wire.h>

#define SCL 15 // IO15 GPIO15 HSPI_WSO HS2_CMD SD-Conn
#define SDA 14 // IO14 GPIO14 HSPI_CLK HS2_CLK SD-Conn

#include "PCF8574.h" // PCF8574 library @ 2.3.7
#define PCF_INTERRUPT 0 // IO0 GPIO0 CAM_PIN_XCLK or CSI_MCLK (Interrupt pin for Encoder & Switch)

// Pre-formatted Header for the Interrupt (See initialization of updateEncoder Interrupt Below),
// necessary because of the Interrupt initialization in the next line
void IRAM_ATTR updateEncoder(); // ! *** IRAM_ATTR because this is the ISR !!!

// Initialize PCF-library Interrupt
PCF8574 pcf8574(0x38, PCF_INTERRUPT, updateEncoder); // for Default I2C Pins

Result:

• Init pcf8574…begin(sda, scl) -> 21 22
• Using interrupt pin (not all pins support interrupts)
• STATUS –> 4
• NOT OK <== Wrong SDA and SCL port

After Change

#include <Wire.h>

#define SCL 15 // IO15 GPIO15 HSPI_WSO HS2_CMD SD-Conn
#define SDA 14 // IO14 GPIO14 HSPI_CLK HS2_CLK SD-Conn

#include "PCF8574.h" // PCF8574 library @ 2.3.7
#define PCF_INTERRUPT 0 // IO0 GPIO0 CAM_PIN_XCLK or CSI_MCLK (Interrupt pin for Encoder & Switch)

// Pre-formatted Header for the Interrupt (See initialization of updateEncoder Interrupt Below),
// necessary because of the Interrupt initialization in the next line
void IRAM_ATTR updateEncoder(); // ! *** IRAM_ATTR because this is the ISR !!!

// Initialize PCF-library SDA & SCL
PCF8574 pcf8574(0x38, SDA, SCL);

Question: How to also setup the PCF_INTERRUPT?

Result:

• Init pcf8574…begin(sda, scl) -> 14 15 <== This is OK now
• But also need the Interrupt setup. How to do this?
• STATUS –> 4
• NOT OK <== Why is it still showing NOT OK?

• This topic was modified 10 months, 1 week ago by Renzo Mischianti. Reason: reformat

[Renzo Mischianti]

Hi,
for the interrupt you can use this constructor:

	PCF8574(uint8_t address, int sda, int scl, uint8_t interruptPin,  void (*interruptFunction)());

And the code become like so

#define INTERRUPTED_PIN D7
 
void ICACHE_RAM_ATTR interruptFunction();
 
// initialize library
PCF8574 pcf8574(0x38, SDA, SCL, INTERRUPTED_PIN, interruptFunction);

Bye Renzo

[MAWMN]

In the mean time I have also tested my last code with esp8266, and this works flawlossly, without any error, so why is the esp32 giving me a problem with the Wire library (Timeout)
“[392120][E][Wire.cpp:513] requestFrom(): i2cRead returned Error 263”

thanks, MAWMN

[MAWMN]

obviously my upload was to big so I repacked it again : sorry for this

[MAWMN]

Still Struggeling..

Trying to reconfig SDA & SCL to NON Default pins on ESP32-CAM AI-Thinker board, NOT Working for PCF8574 Library, does work at the same time for U8g2 Library ?

gives problems with the PCF8574 while the SSD display works fine with it: 
Monitoring loop Started..
Init pcf8574...OK
but after constantly changing the content of the display (Seconds wise), all interrupts of the PCF8574 give :
[ 55886][E][Wire.cpp:513] requestFrom(): i2cRead returned Error 263 

#include <Arduino.h>
#include <stdint.h>
#include <esp_camera.h>

//* for I2C
#include <Wire.h> 
TwoWire I2C_PINS_NON_DEFAULT = Wire;   // Try to reconfig the wire Lib to use NON Default Pins

#define SCL 15                         // IO15  GPIO15  HSPI_WSO  HS2_CMD     SD-Conn
#define SDA 14                         // IO14  GPIO14  HSPI_CLK  HS2_CLK     SD-Conn

#define SETBUSSPEED                    // We do want to set the BusSpeed
#undef SETBUSSPEED                     // We do NOT want to set the BusSpeed

#ifdef SETBUSSPEED
  #define BUSSPEED 100000U             // BusSpeed = 100.000 kHz
  // #define BUSSPEED 400000U             // BusSpeed = 400.000 kHz
#endif

//* SDD1306 Config
#include <U8x8lib.h>    // I2C (Maximum Speed SCL +/- 400 kHz)                                      // ! Text Only Library
U8X8_SSD1306_128X64_NONAME_SW_I2C u8x8(/* clock=*/ SCL, /* data=*/ SDA, /* reset=*/ U8X8_PIN_NONE); // ! Text Only (from long list)

//* PCF8574 MultiClick
#include "PCF8574.h"
#define PCF_INTERRUPT 0				         // IO0   GPIO0   CAM_PIN_XCLK or CSI_MCLK (Interrupt pin for Encoder & Switch)

// * RotaryEncoder defines (Connected to PCF8574)
#define encoderPinA  			P0
#define encoderPinB  			P1
#define switchPin					P2

// Forward declaration for the Interrupt (See Initialisation of isr_updateEncoder ISR Below), 
//   necessary here because of the Interrupt Initialisation in the next Line
void IRAM_ATTR isr_updateEncoder();	

// Initialize PCF-library for used address, SDA & SCL, Interrupt function
PCF8574 pcf8574(0x38, SDA, SCL, PCF_INTERRUPT, isr_updateEncoder);
  

void IRAM_ATTR isr_updateEncoder() {
  //! DO NOT Read pcf8574.readEncoderValue(encoderPinA, encoderPinB, &encoderValue);
  //!         and pcf8574.digitalRead(switchPin); in the isr_updateEncoder() function here !!!
  //!  this will cause "Guru Meditation Error: Core  1 panic'ed (Interrupt wdt timeout on CPU1)"
  //!  Keep the interrupt function as short as possible and only set a flag here !!!
  //!  Next in the main loop() DO Read these values by the function getEncValues() and checkButton() !!!
  changed = true;
}

void ClrScr() {
  // ! *** See : https://github.com/olikraus/u8g2/wiki/u8x8reference
  u8x8.clear();
  delay(50);
  u8x8.clearDisplay();
  delay(50);
  u8x8.setFont(u8x8_font_chroma48medium8_r);      // Normal=1, Larger=2, largest=3, :1 pixel scale
  delay(50);                                      // See : https://github.com/olikraus/u8g2/wiki/fntlist8x8
  u8x8.print("");                                 // Draw text
  delay(50);
  u8x8.flush();
  delay(50);
}

void Display_Init() {    // ! *** Text Only
  u8x8.begin();                               // Start the Display Object, with NO PowerSaving
  delay(250);                                 // ! *** Extended delay 50 ==> 250 : See datasheet 18-12-2023 page 18 & 32
  u8x8.initDisplay();
  delay(50);         
  u8x8.setPowerSave(0);                       // Seems essentieel, for correct new start !!!
  delay(50);
  ClrScr();
}

void Display_Text(byte XPos, byte YPos, bool Invert, byte FieldSize, String MyText) {
  // u8x8 library only has LineMode (TEXT Only), for graphics use u8g2 library !!!
  // ! *** When using Graphics we are adressing X and y at pixel level !!!
  // ! *** When using Text Only we are adressing X and y at line level !!!
  // Set Font
  u8x8.setFont(u8x8_font_chroma48medium8_r);    // Small FontSize - 16 char/line
                                                // See : https://github.com/olikraus/u8g2/wiki/fntlist8x8

  // Set Normal / Inverse
  if (Invert == false) {
    u8x8.setInverseFont(0);                     // Draw 'normal' text
  } else {
    u8x8.setInverseFont(1);                     // Draw 'inverse' text
  }

  String NewStr = MyText; // Set for when FieldSize is set to 0 (NO Size Control) OR Correct !!!
  if (FieldSize != 0) {
    // Control the Length of the Text Field
    if (MyText.length() > FieldSize) {
      // MyText too long
      NewStr = "";
      for (size_t i = 1; i < FieldSize; i++) NewStr = NewStr + MyText[i];
    }

    if (MyText.length() < FieldSize) {
      // MyText too short
      NewStr = MyText;
      while (NewStr.length() < FieldSize) NewStr = NewStr + " ";
    }
  }
  u8x8.drawString(XPos, YPos, NewStr.c_str());
  u8x8.flush();
}

void setup() {
  //* Init Serial
  Serial.begin(115200);
  delay(3000);              //! We Need at least 3 seconds to start up the serial port for monitoring @ ESP32-Cam in PlatformIO !!!

  I2C_PINS_NON_DEFAULT.begin(SDA, SCL);

  //* Init OLED-Display
  Display_Init();           // Initialize the display and Start Showing the Information

  // Show texts @ the SSD Display
  mText = "Config.Finished.";
  Display_Text(0, 1, false, 16, mText);

  mText = "M.A.W.M. Nijland";
  Display_Text(0, 3, false, 16, mText);

  mText = "Apeldoorn - 2024";
  Display_Text(0, 5, false, 16, mText);

  Serial.println("\nMonitoring loop Started..");
  Serial.flush();

  //* Initialize ESP-CAM Interrupt Input
  pinMode(PCF_INTERRUPT, INPUT_PULLUP);

	//* Init PCF8574 pins	
  pcf8574.pinMode(encoderPinA, INPUT_PULLUP);   // Encoder A
  pcf8574.pinMode(encoderPinB, INPUT_PULLUP);   // Encoder B

	// Encoder pins
	pcf8574.encoder(encoderPinA, encoderPinB);

	// Encoder button
	pcf8574.pinMode(switchPin, INPUT_PULLUP);

  delay(100);

	// Start the PCF8574 library
	Serial.print("Init pcf8574...");
	if (pcf8574.begin(0x38)) {
		// Board/Chip is Acknowledging the I2C Commands
		Serial.println("OK");
	} else {
		// Board/Chip is NOT Acknowledging the I2C Commands
		Serial.println("NOT OK");
	}
}

loop() {
  // etc. etc..
}

[LillianSkye]

It helped me, Thank you.

[MAWMN]

Hello, can you be more specific, were you able to solve my problem ?? because I still did not find the solution for the reported errr : [ 55886][E][Wire.cpp:513] requestFrom(): i2cRead returned Error 263 ??

thanks

[Author]

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