I2C - Inter-Integrated Circuit

I2C Class in the Reference.

Hardware I2C

On most boards there are hardware I2C peripherals. Check out the pin diagram on the reference page for your board and look for pins marked with an I2C tag.

You can use it as follows.

// set up I2C
I2C1.setup({ scl : B6, sda: B7 });

// read 6 bytes from address 0x52
var d = I2C1.readFrom(0x52, 6);

// Write a single byte (0) to address 0x52
I2C1.writeTo(0x52, 0);

See the reference for I2C.setup for more information on the arguments that can be passed in.

Software I2C

If you don't have access to your board's pins, you can also emulate I2C in software:

// set up I2C
var i2c = new I2C();
i2c.setup({ scl : B6, sda: B7 });

// read 6 bytes from address 0x52
var d = i2c.readFrom(0x52, 6);

// Write a single byte (0) to address 0x52
i2c.writeTo(0x52, 0);

See the reference for I2C.setup for more information on the arguments that can be passed in.

Speed (bit rate)

Pretty much all I2C devices are guaranteed to support 100kBits/sec transfer speed for I2C, so that is the default in Espruino. However you can specify higher speeds with bitrate in I2C.setup if your device supports it, eg:

i2c.setup({ scl : B6, sda: B7, bitrate: 400000 });

Using I2C

AHT10 RH/TEMP Sensor BH1792 I2C Heart rate Sensor TMP117 Temperature Sensor MLX90632 non-contact temperature sensor MAX30102 Heart rate monitor HD44780 Character LCD INA226 Current/Voltage Measurement IC INA219 Zero-Drift, Bidirectional Current/Power Monitor With I2C Interface SSD1306 OLED driver VL53L1X SH1106 OLED driver PN532 NFC/RFID module MS5803 Pressure Sensor VL53L0X Wii Nunchuck MLX90614 Infra Red thermometer MAG3110 3-axis magnetometer HP03S pressure sensor module SSD1327 OLED driver MMC212xMG Dual-axis Magnetic Sensor from MEMSIC used in HDMM01 breakout from Pollin MAX1704x Battery Fuel Gauge ADS1x15 programmable gain ADC MCP794xx Battery-Backed I2C Real-Time Clock/Calendar with SRAM, (optional) EEPROM and Protected EEPROM SHT4x Temperature and Humidity sensor LIS3DH Accelerometer BH1750 I2C Light Sensor SHT3C Temperature and Humidity sensor Sensirion SHT20, SHT21 & SHT25 Temperature and Relative Humidity Sensor OPT3001 Light Sensor LPS22HB pressure sensor MAX44009 I2C Ambient Light Sensor CCS811 Digital Air Quality Sensor AT24Cxxx I2C EEPROM and FRAM (incl. M24M02, MB85RCxx, FT24Cxxx, 24LCxxx, CAT24Cxxx, BR24Gxxx) BME280 Environment sensor PCA9685 Port Expander IS31FL3731 Charlieplexed LED controller APDS9960 Light and gesture sensor SH1107 OLED driver BME680 Environment sensor MPU9250 accelerometer/gyro/magnetometer LIS2MDL Magnetometer LSM303DLHC Accelerometer TSL2561 Luminosity sensor TCS3472x I2C Color Sensor SI7021(-A20) I2C Temperature and Humidity Sensor LSM6DSL Accelerometer and 3D Gyroscope HTU21D Temperature and RH Sensor BH1745 Digital Color Sensor HTS221 humidity and temperature sensor BMP280 Environment sensor MPU6050 accelerometer and gyro MPL3115A2 Digital Altitude / Pressure / Temperature Sensor MPL115A2, I2C digital barometer and temperature sensor MCP9808 precision I2C temperature sensor MCP4xxx I2C and SPI digital potentiometers MCP23xxx I2C and SPI port expanders LPS25HB pressure sensor Digole LCD driver (monochrome) CAP1188 capacitive touch breakout BMP085/BMP180 digital pressure sensor