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flipper-zero-tutorials/gpio/i2c_demo/README.md
Derek Jamison 0fb6fb32d1 Initial code for i2c_demo
2023-03-21 10:08:36 -04:00

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I2C DEMO

Introduction

This is a basic demonstration of reading/writing I2C protocol. For this demo, we connect a I2C device to pins:

  • 3V3 (3V3, pin 9) = VCC
  • GND (GND, pin 18) = GND
  • SCL (C0, pin 15) = SCL
  • SDA (C1, pin 16) = SDA

Installation Directions

This project is intended to be overlayed on top of an existing firmware repo.

  • Clone, Build & Deploy an existing flipper zero firmware repo. See this tutorial for updating firmware.
  • Copy the "i2c_demo" folder to the \applications\plugins\i2c_demo folder in your firmware.
  • Build & deploy the firmware. See this tutorial for updating firmware.
  • NOTE: You can also extract the i2c_demo.FAP from resources.tar file and use qFlipper to copy the file to the SD Card/apps/Gpio folder.

Running the updated firmware

These directions assume you are starting at the flipper desktop. If not, please press the back button until you are at the desktop.

  • Press the OK button on the flipper to pull up the main menu.

  • Choose "Applications" from the menu.

  • Choose "GPIO" from the sub-menu.

  • Choose "I2C Demo"

  • The flipper should say "I2C NOT FOUND" if no I2C devices are connected.

  • NOTE: If your I2C device already has pull-up resistors, then you do not need to add them to your SCL and SDA lines.

  • Connect an I2C device (like a BH1750) to pins 9 (3V3), 15 (SCL), 16 (SDA), 18 (GND).

  • The message should change to "FOUND I2C DEVICE"

  • The next line should have the address of the I2C device.

  • If the device is a BH1750 then you should also see "WRITE/READ SUCCESS" and a value that changes with the brightness on the sensor.

  • Press the BACK button to exit.

How it works

  • application.fam

    • specifies the name of our application.
    • specifies the entry point for our application.
    • specifies we use the GUI.
    • specifies our icon is the i2c_demo.png file.
    • specifies our application can be found in the "GPIO" category.

  • i2c_demo.png

    • The icon for our application that shows up in the "GPIO" folder.

  • i2c_demo_app.c

    • This is the demo application that uses I2C.