Inter-Integrated Circuit (I2C)

The Inter-Integrated Circuit by Philips is a popular interconnect (typically on-board) used on embedded processors as well as modern computers consisting of 2-wires (other than ground, power, and optional interrupts):

• SCL - clock
• SDA - data

An I2C bus may be multi-master and support interrupts from the device to host controller.

Reference:

• ​http://en.wikipedia.org/wiki/I%C2%B2C

On-Board I2C Host Controllers

Various Gateworks boards support 3.3V TTL I2C to an off-board expansion connector:

Family	Board	Device	I2C Buffer Enable	Connector
Venice	GW740x	I2C4 /dev/i2c-3	-	J14 DIO: J14.5 SCL, J14.6 SDA J8 MIPI: J8.34 SCL, J8.36 SDA
	GW730x	I2C3 /dev/i2c-2	-	J9 (shared with MIPI J17)
	GW720x	I2C3 /dev/i2c-2	-	J5 (shared with MIPI J4)
	GW710x	I2C3 /dev/i2c-3	-	J25
Newport	GW610x	TWSI1 /dev/i2c-1	-	J10 (dedicated SDA/GND/SCL) 3.3V TTL
	GW620x	TWSI1 /dev/i2c-1	-	J11 (dedicated SDA/GND/SCL) 3.3V TTL (build option for 5V TTL)
	GW630x	TWSI1 /dev/i2c-1	-	J14 (dedicated SDA/GND/SCL) 3.3V TTL (build option for 5V TTL)
	GW640x	TWSI1 /dev/i2c-1	-	J14 (dedicated SDA/GND/SCL) 3.3V TTL (build option for 5V TTL)
Ventana	GW54xx-B+	I2C3 /dev/i2c-2	gpio101	J16 (shared with DIO0/DIO1) 1
	GW53xx-B+	I2C3 /dev/i2c-2	gpio101	J4 (shared with DIO0/DIO1) 1
	GW52xx-C+	I2C3 /dev/i2c-2	-	J4 (shared with DIO0/DIO1) 1 2
	GW551x	I2C3 /dev/i2c-2	-	J3 (dedicated SDA/SCL/GND)

1. Ventana off-board I2C shares pins with MX6_DIO0 / MX6_DIO1 which need to be configured as inputs to use I2C
2. requires resistor loading option

Please consult the ​Hardware Manuals for pinouts

See also:

• Ventana I2C

USB I2C Host Controllers

A I2C master can also be added via USB expansion. For example:

• GW16113 firmware-flexible USB 2.0 FS expansion
• ​Commell MPX-24794S USB 2.0 FS SPI/I2C/GPIO expansion

Linux Kernel API

See linux/i2c