The __Inter-integrated Circuit (I%%sup 2%%​C) Protocol__ (pronounced ''I-squared-C'' ) is a hardware serial interface (or "protocol") intended to allow multiple "slave" components to communicate with one or more "master" components. It used across many microprocessors and microcontrollers, including the [Raspberry Pi]. I2C permits sensors and other IO devices to be connected to the controller (and/or each other) with only four wires (or really only ''two'' if you don't count Vcc and ground): # __3-6V__ (Vcc) # __SDA__ (Serial Data Line) # __SCL__ (Serial Clock Line) # __GND__ (Ground) The Pimoroni "Breakout Garden" set of I2C sensors also includes an "__{{{INT}}}__" (interrupt) pin, ''AKA'' "{{{GCLK}}}" or "{{{GPIO4}}}". !! To View the Current I2C Devices To see what's connected on your Raspberry Pi, type (not including the {{{%}}} prompt): {{{ % i2cdetect -y 1 }}} and you'll see something like: {{{ 0 1 2 3 4 5 6 7 8 9 a b c d e f 00: -- -- -- -- -- -- -- -- -- -- -- -- -- 10: -- -- -- -- 14 15 -- -- -- -- -- -- -- -- -- -- 20: -- -- -- -- -- -- -- -- 28 -- -- -- -- -- -- -- 30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 60: -- -- -- -- -- -- -- -- 68 -- -- -- -- -- -- -- 70: -- -- -- -- 74 75 -- 77 }}} !! Known I2C Devices Some well known I2C products. No two I2C may share the same address on an I2C bus, otherwise there will be contention. || Stock || Brand || Description || 7 bit address || Notes | 1 | Pimoroni | LTR-559 Light & Proximity | 0x23 | | 1 | Pimoroni | VL53L1X Time of Flight (ToF) | 0x29 | range 40mm-4m | 1 | Adafruit | VL6180X Time of Flight Distance Sensor | 0x29 | range 5-100mm | 1 | Pimoroni | 11x7 LED Matrix #1 | 0x75 | | 1 | Pimoroni | 11x7 LED Matrix #2 | 0x77 | | 1 | Pimoroni | 5x5 RGB Matrix | 0x74 / 0x77 | 77 will be in conflict with 11x7 #2 | 1 | Pimoroni | [ADS1015 +/-24V ADC 3 Channel|Ads1015AnalogDigitalConverter] | 0x48 / 0x49 | | 2 | Adafruit | ADS1015 12 bit ADC 4 Channel w Prog Gain | 0x48 - 0x4B (jumpers) | | 1 | PiBorg | Thunderborg | 0x10 / 0x11 | | 1 | PiBorg | Ultraborg | 0x36 | | 1 | Pimoroni | ICM20948 9-DOF Motion Sensor | 0x68 / 0x69 | | 1 | Adafruit | BNO055 Absolute Orientation Sensor | 0x28 / 0x29 | | 0 | Adafruit | VCNL4010 Proximity Sensor | 0x13 | | 0 | Adafruit | LSM9DS1 Accel Gyro Mag Temp 9-DOF | 0x1C / 0x1E Accel, 0x6A / 0x6B for Gyro | | 0 | Adafruit | VL53L0X Time of Flight Distance Sensor | 0x29 | range 50-1200mm (2m on long range) "Stock" is how many [Murray] has in his robot laboratory as part of exploratory design and development of the [KR01] robot. !! Links * [I2C|https://en.wikipedia.org/wiki/I%C2%B2C] on Wikipedia * [Configuring I2C|https://learn.adafruit.com/adafruits-raspberry-pi-lesson-4-gpio-setup/configuring-i2c] from AdaFruit * [I2C|https://learn.sparkfun.com/tutorials/i2c] on SparkFun * [Raspberry Pi SPI and I2C Tutorial|https://learn.sparkfun.com/tutorials/raspberry-pi-spi-and-i2c-tutorial/all] ---- [{Tag Hardware}]