problem with ssd1306 and pcf8574 on i2c port (solved)

[alirezaimi]

Hi Is there any known problem with ssd1306 ? after Pinmode and begin for this module, the ssd1306 commands not work at all !

I use Adafruit_SSD1306 library for my 0.96 oled and your library for my pcf8574 .

[xreef]

Hi Alizeraimi, you use pcf with interrupt?? Bye Renzo

[alirezaimi]

No @xreef, for now just using other ports. I searched little bit and find out something related to clock speed, is this right ? If it's true how can I change these two to work together ?

[xreef]

Hi Alirezaimi, I use ssd1306 with pcf8574 anche I had problem only when use interrupt, in the nexts weeks I'm going to write an article on ssd1306 and pcf8574 (I develope attachInterrupt and detachInterrupt) with interrupt and I check better if there are other problems.

I use this code to work all together.

    if (changed){
        SERIAL_DEBUG.print("ENCODER --> ");
        SERIAL_DEBUG.print(encoderValue);
        SERIAL_DEBUG.print(" - BUTTON --> ");
        SERIAL_DEBUG.println(encoderButtonVal?"HIGH":"LOW");

        pcf8574.detachInterrupt();
        if (changedButton) {
            currentScreen = clickMenu(currentScreen, encoderValue);
            changedButton = false;
        }

        renderScreen(currentScreen);

        display.clearDisplay();

        pcf8574.attachInterrupt();
        changed = false;
        pcf8574.readEncoderValue(ENCODER_PIN_A, ENCODER_PIN_B);
        pcf8574.digitalRead(ENCODER_BUTTON);
    }

i use Adafruit library too, when I have more information I write here.

Bye Renzo

[alirezaimi]

Thanks, but what can I do for solving my problem ????? Changing clock speed is the solution or not ?

[xreef]

Hi alirezaimi, specify the platform you use and put your code here. https://www.mischianti.org/forums/forum/yours-project/

I'm going to check your problem. I try locally, and for me work without problem, but I try to do more test.

Bye Renzo

[alirezaimi]

After I changed my code and test some pints on it, i find out that because i using another ports than default port that declared in adafriut library for ssd1306 and wire library (d4, d5), and i using d6 and d7 ports instead , my project not worked,

If i put Wire.begin() before pcf8574 pinmodes the ssd1306 not work, but if i put it after pinmodes its worked!

This code not work :

void setup() {
  Serial.begin(115200);
  delay(10);

// oled settings
  Wire.begin(OLED_SDA, OLED_SCK);  // oled change default i2c pins from d4 and d5  

  expander.pinMode(P0, INPUT_PULLUP); // touch 1
  expander.pinMode(P1, OUTPUT);  // relay 1
  expander.pinMode(P2, OUTPUT); // relay 2
  expander.pinMode(P3, INPUT_PULLUP); // touch 2
  expander.begin();

  // SSD1306_SWITCHCAPVCC = generate display voltage from 3.3V internally
  if(!display.begin(SSD1306_SWITCHCAPVCC, OLED_SCREEN_ADDRESS)) {
    Serial.println(F("SSD1306 allocation failed"));
    for(;;); // Don't proceed, loop forever
  }
  // Show initial display buffer contents on the screen --
  // the library initializes this with an Adafruit splash screen.
  display.display();
  // Clear the buffer
  display.clearDisplay();
  // Draw a single pixel in white
  display.drawPixel(10, 10, SSD1306_WHITE);
  // Show the display buffer on the screen. You MUST call display() after
  // drawing commands to make them visible on screen!
  display.display();
  ...

and this one worked :

void setup() {
  Serial.begin(115200);
  delay(10);

  expander.pinMode(P0, INPUT_PULLUP); // touch 1
  expander.pinMode(P1, OUTPUT);  // relay 1
  expander.pinMode(P2, OUTPUT); // relay 2
  expander.pinMode(P3, INPUT_PULLUP); // touch 2
  expander.begin();

// oled settings
  Wire.begin(OLED_SDA, OLED_SCK);  // oled change default i2c pins from d4 and d5  

  // SSD1306_SWITCHCAPVCC = generate display voltage from 3.3V internally
  if(!display.begin(SSD1306_SWITCHCAPVCC, OLED_SCREEN_ADDRESS)) {
    Serial.println(F("SSD1306 allocation failed"));
    for(;;); // Don't proceed, loop forever
  }
  // Show initial display buffer contents on the screen --
  // the library initializes this with an Adafruit splash screen.
  display.display();
  // Clear the buffer
  display.clearDisplay();
  // Draw a single pixel in white
  display.drawPixel(10, 10, SSD1306_WHITE);
  // Show the display buffer on the screen. You MUST call display() after
  // drawing commands to make them visible on screen!
  display.display();
  ...

[alirezaimi]

And now pcf not work anymore :(

[xreef]

Hi Alirezaimi, check the documentation on https://www.mischianti.org/2019/01/02/pcf8574-i2c-digital-i-o-expander-fast-easy-usage/ and use correct pcf constructor. If you use different sda scl you must specify different SDA SCL on pcf.

PCF8574(uint8_t address, uint8_t sda, uint8_t scl);

Bye Renzo

[alirezaimi]

My bad :((((( I change a port of i2c by mistake . thanks a lot .