SparkFun Forums

[DizietAsahi]

Hi,
For the life of me, I cannot get two Artemis RedBoard to talk to each other over I2C and I don't understand why.

I have stripped everything from the boards the only connections I have are (top right of the board, near the USBC connector)

Controller Target
-------------- ---------
SCL <------------------> SCL
SDA <------------------> SDA
GND <------------------> GND

I uploaded the code from [the Arduino doc](https://docs.arduino.cc/learn/communication/wire/)

Controller:

Code: Select all

// Wire Controller Reader
// by Nicholas Zambetti [http://www.zambetti.com](http://www.zambetti.com)

// Demonstrates use of the Wire library
// Reads data from an I2C/TWI peripheral device
// Refer to the "Wire Peripheral Sender" example for use with this

// Created 29 March 2006

// This example code is in the public domain.


#include <Wire.h>

void setup() {
  Wire.begin();        // join i2c bus (address optional for master)
  Serial.begin(9600);  // start serial for output
}

void loop() {
  Wire.requestFrom(8, 6);    // request 6 bytes from peripheral device #8

  while (Wire.available()) { // peripheral may send less than requested
    char c = Wire.read(); // receive a byte as character
    Serial.print(c);         // print the character
  }

  delay(500);
}

Target:

Code: Select all

// Wire Peripheral Sender
// by Nicholas Zambetti [http://www.zambetti.com](http://www.zambetti.com)

// Demonstrates use of the Wire library
// Sends data as an I2C/TWI peripheral device
// Refer to the "Wire Master Reader" example for use with this

// Created 29 March 2006

// This example code is in the public domain.


#include <Wire.h>

void setup() {
  Wire.begin(8);                // join i2c bus with address #8
  Wire.onRequest(requestEvent); // register event
}

void loop() {
  delay(100);
}

// function that executes whenever data is requested by master
// this function is registered as an event, see setup()
void requestEvent() {
  Wire.write("hello "); // respond with message of 6 bytes
  // as expected by master
}

I am not seeing anything on the serial terminal. These are the signals that I see on the I2C bus (blue is SCL, yellow is SDA):

PXL_20240301_190641384.jpg

I have tested the exact same code between two esp32 and everything works as expected.

PXL_20240301_191019386.jpg

I don't understand what I am doing wrong.

[DizietAsahi]

BTW, I also tried using a QWIIC cable between the two artemis, no luck. The Qwiic cable works between the two ESP32.

[paulvha]

The Sparkfun Artemis Wire library does NOT support slave(peripheral) mode. It can only act as a Master (controller).
It is half-documented in the README on https://github.com/sparkfun/Arduino_Apollo3, but it is 100% sure as there is NO code to handle it.

You can connect an ESP32 as a peripheral to an Artemis running as a controller.

[DizietAsahi]

I see, thank you for the link. I had overlooked that part