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Topic: esp32 and i2c (Read 250 times) previous topic - next topic

vsl

I'm not sure if this is the correct section, but....

I have a DOIT esp32 devkit V1 board and I can't get any response from the I2C pins. I have 2 peripheral boards(BMP280 and TSL2561) both of which work fine on a UNO. Im running IDE 1.8.11 with the ESP additions.

I've tried using many pairs of pins in addition to the default pair(21,22) but no response from any of them. I've tried running the I2C at different speeds as dictated by the wire.begin, but again no response.

I beleive this is the ubiquitous I2c test code which returns "no I2C devices found"

Code: [Select]
// --------------------------------------
    // i2c_scanner
    //
    // Version 1
    //    This program (or code that looks like it)
    //    can be found in many places.
    //    For example on the Arduino.cc forum.
    //    The original author is not know.
    // Version 2, Juni 2012, Using Arduino 1.0.1
    //     Adapted to be as simple as possible by Arduino.cc user Krodal
    // Version 3, Feb 26  2013
    //    V3 by louarnold
    // Version 4, March 3, 2013, Using Arduino 1.0.3
    //    by Arduino.cc user Krodal.
    //    Changes by louarnold removed.
    //    Scanning addresses changed from 0...127 to 1...119,
    //    according to the i2c scanner by Nick Gammon
    //    https://www.gammon.com.au/forum/?id=10896
    // Version 5, March 28, 2013
    //    As version 4, but address scans now to 127.
    //    A sensor seems to use address 120.
    // Version 6, November 27, 2015.
    //    Added waiting for the Leonardo serial communication.
    //
    //
    // This sketch tests the standard 7-bit addresses
    // Devices with higher bit address might not be seen properly.
    //
     
    #include "Wire.h"
    #define SCL_PIN 22
    #define SDA_PIN 21

    void setup()
    {
      Wire.begin(SDA_PIN,SCL_PIN,400000);
     
      Serial.begin(19200);
      while (!Serial);             // Leonardo: wait for serial monitor
      Serial.println("\nI2C Scanner");
    }
     
     
    void loop()
    {
      byte error, address;
      int nDevices;
     
      Serial.println("Scanning...");
     
      nDevices = 0;
      for(address = 1; address < 127; address++ )
      {
        // The i2c_scanner uses the return value of
        // the Write.endTransmisstion to see if
        // a device did acknowledge to the address.
        Wire.beginTransmission(address);
        error = Wire.endTransmission();
     
        if (error == 0)
        {
          Serial.print("I2C device found at address 0x");
          if (address<16)
            Serial.print("0");
          Serial.print(address,HEX);
          Serial.println("  !");
     
          nDevices++;
        }
        else if (error==4)
        {
          Serial.print("Unknown error at address 0x");
          if (address<16)
            Serial.print("0");
          Serial.println(address,HEX);
        }   
      }
      if (nDevices == 0)
        Serial.println("No I2C devices found\n");
      else
        Serial.println("done\n");
     
      delay(5000);           // wait 5 seconds for next scan
    }


anybody got any suggestions?

BJHenry

Do you have pullup resistors on the SDA and SCL lines?

vsl

yes I have 3k pullups on both lines. I've tried with and without but get the same result.

vsl

my apologies chaps....

it was a duff breadboard with suspect contacts...

mea culpa

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