IC2 - Communication between two Teensys 4.1

[8JupiterMoll8]

Hallo,

I'm triyng to send Data over IC2 from a Teensy 4.1 (Master) >>> to >>> Teensy 4.1 (Slave)

Both Teensys are grounded together and use SCL Pin : 19 and SDA Pin : 18. The Wires are short.

Can you tell me which code example of your library i have to use for the master sender and the slave -reciver.

Thx.

[8JupiterMoll8]

In file included from C:\Users\Jupiter Moll.platformio\packages\framework-arduinoteensy\libraries\Wire/Wire.h:26:0, from C:\Users\Jupiter Moll.platformio\packages\framework-arduinoteensy\libraries\EasyTransferI2C/EasyTransferI2C.h:45, from src\main.cpp:22: C:\Users\Jupiter Moll.platformio\packages\framework-arduinoteensy\libraries\Wire/WireIMXRT.h:191:16: error: conflicting declaration 'TwoWire Wire' extern TwoWire Wire; ^ In file included from src\main.cpp:21:0: lib\teensy4_i2c-master\src/i2c_driver_wire.h:150:22: note: previous declaration as 'I2CDriverWire Wire' extern I2CDriverWire Wire; // Pins 19 and 18; SCL0 and SDA0 ^ In file included from C:\Users\Jupiter Moll.platformio\packages\framework-arduinoteensy\libraries\Wire/Wire.h:26:0, from C:\Users\Jupiter Moll.platformio\packages\framework-arduinoteensy\libraries\EasyTransferI2C/EasyTransferI2C.h:45, from src\main.cpp:22: C:\Users\Jupiter Moll.platformio\packages\framework-arduinoteensy\libraries\Wire/WireIMXRT.h:192:16: error: conflicting declaration 'TwoWire Wire1'
extern TwoWire Wire1; ^ In file included from src\main.cpp:21:0: lib\teensy4_i2c-master\src/i2c_driver_wire.h:151:22: note: previous declaration as 'I2CDriverWire Wire1' extern I2CDriverWire Wire1; // Pins 16 and 17; SCL1 and SDA1 ^ In file included from C:\Users\Jupiter Moll.platformio\packages\framework-arduinoteensy\libraries\Wire/Wire.h:26:0, from C:\Users\Jupiter Moll.platformio\packages\framework-arduinoteensy\libraries\EasyTransferI2C/EasyTransferI2C.h:45, from src\main.cpp:22: C:\Users\Jupiter Moll.platformio\packages\framework-arduinoteensy\libraries\Wire/WireIMXRT.h:193:16: error: conflicting declaration 'TwoWire Wire2'
extern TwoWire Wire2; ^ In file included from src\main.cpp:21:0: lib\teensy4_i2c-master\src/i2c_driver_wire.h:152:22: note: previous declaration as 'I2CDriverWire Wire2' extern I2CDriverWire Wire2; // Pins 24 and 25; SCL2 and SDA2 ^ *** [.pio\build\ IC2_SEND\src\main.cpp.o] Error 1 ================================================================ [FAILED] Took 3.49 seconds ================================================================The terminal process "C:\Users\Jupiter Moll.platformio\penv\Scripts\platformio.exe 'run', '--target', 'upload', '--environment', ' IC2_SEND'" terminated with exit code: 1.

[Sorin-Jayaweera]

Hi, did you get it working? Could you post your basic master writer code, and the slave_reciever(if different from the example) you're using? Thanks!

[Sorin-Jayaweera]

*also, are you using 2.2k 3.3 pullup resistors for both scl and sda, or do you not need them? I'm not sure if the om board small ones are enough. Thanks!

[8JupiterMoll8]

Hi:

Check this link for SDA and SCL Pinds and Resistor values : https://www.pjrc.com/teensy/td_libs_Wire.html

Teeny 4.1 RECIVER:

#include <i2c_driver.h>
#include <i2c_driver_wire.h>

struct TransmitData
{
  float x;
  float y;
};

TransmitData data;

void setup()
{

  Wire.begin();                         // join i2c bus
  Serial.begin(9600);               // start serial for output
  while(!Serial) { }
}

void loop()
{
  Serial.print("requesting ("); 
  Serial.print(sizeof data); 
  Serial.print(" bytes)... ");
  if (Wire.requestFrom(0x40, sizeof data))
  {
    Wire.readBytes((byte*) &data, sizeof data);
    Serial.println("done");

    Serial.println(data.x);
    Serial.println(data.y);

  } 
  else {
    Serial.println("could not connect");
  }
 // delay(500);
}`

the other Teensy 4.1 SENDER:

#include <i2c_driver.h>
#include <i2c_driver_wire.h>

struct TransData
{
  float x;
  float y;        
};

TransData data;

void requestEvent();

void setup()
{

  Wire.begin(0x40);        // join i2c bus with address #8
  Wire.onRequest(requestEvent); // register event
  //Wire.setClock(1000000);

  Serial.begin(9600);
  while(!Serial) { }

}

void loop()
{
  data.x = 1.0;
  data.y = 2.0;
}

// function that executes whenever data is requested by master
// this function is registered as an event, see setup()
void requestEvent()
{
  Serial.print("sending ("); 
  Serial.print(sizeof data);
  Serial.println(" bytes)");

  Wire.write((byte *)&data, sizeof data);
}

Good luck... Greetings from Berlin

[Sorin-Jayaweera]

Thank you so much! I plugged the teensies directly into each other, without the pullup pins, used your code, boom works!

[Richard-Gemmell]

I'm glad to hear you've both got your setups working. Thanks for helping out 8JupiterMoll8.