Simple Teensy 4.1 Slave, what am I missing?

[arjuna-dev]

I am trying to send data from a Teensy 4.1 as am I2C slave.

Here is an image from a logic analyzer of what I am sending to it:

And I am using the basic example (just modifying the slave address):

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

void requestEvent();

int led = LED_BUILTIN;

void setup()
{
  pinMode(led, OUTPUT);
  Wire.begin(0x22);
  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()
{
  digitalWrite(led, HIGH);      // briefly flash the LED
  Wire.write(0xFF);
  digitalWrite(led, LOW);
}

I am using pins 16 and 17 as a slave I2C in the teensy.

It seems that requestEvent() never kicks in.

Thanks!

[Richard-Gemmell]

Hi, It's a simple mistake. Your code is using Wire which is tells it to use pins 18 & 19. Change all references to Wire1 and it should work. e.g. Wire1.begin(0x22).

The logic analyzer is showing that the master is working and configured correctly.

cheers, Richard