I2C Extend Click Board™

How Does The I2C Extend Click Board™ Work?

The I2C Extend Click Board™ is based on the LTC4331, which is a point-to-point compatible I2C slave device extender designed for operation in high noise industrial environments. Using a ±60V fault protected differential transceiver, the LTC4331 can extend an I2C/SMBus bus, including remote interrupt function and a control signal, over a single twisted pair differential link. Thanks to selectable link baud rates, the I2C bus can be extended up to 1200m, depending on the link speed and external factors such as environmental noise level, humidity, cable quality, etc. Standard twisted-pair cables with RJ45 connectors can be used, the same as in the ethernet devices, etc.

Besides the I2C protocol extension, I2C Extend Click Board™ also supports local to remote control and interrupt functions. Local to remote control ensures that the values set on the local side CTRL pin propagate to the remote side CTRL pin over the differential link. Users can choose pin on the mikroBUS™ socket used for that purpose (CS or RST), using the onboard jumper named PIN SEL. Interrupt pin acts as an open-drain output in local mode and an input in remote mode. Basically, an interrupt signal on the INT pin in the I2C Extend Click is mirrored from the remote network to the local network using the differential link. On the remote side INT is an input pin that can be connected to remote I2C slave devices, while on the local side, it is operating as an open-drain output that can be connected to a shared local interrupt line.

Because of the dual functionality of the I2C Extend Click, the user needs to set the mode of operation of the Click board™. That is easily achieved using the onboard MODE switch, with two positions: local mode (LCL), where this Click board™ is in I2C slave mode and remote mode (RMT) where this Click board™ is in I2C master mode. Besides mode selection, I2C Extend Click can also link speed and I2C address selection jumpers onboard, named "SPEED SEL" and "ADDR SEL", respectively.

The I2C Extend Click Board™ has Link status (LINK) and ready status (RDY) LEDs, making troubleshooting as easy as possible. In remote mode, LINK LED is active when the device establishes link communication. When in local mode, LINK LED is active after the LTC4331's I2C interface has joined the I2C bus in addition to establishing link communication.The RDY LED is active after the device's I2C interface has joined the bus.

The I2C Extend Click Board™ is designed to operate with both 3.3V and 5V logic levels that can be selected via VCC SEL jumper. This allows for both 3.3V and 5V capable MCUs to use the I2C communication lines properly.

SPECIFICATIONS

PINOUT DIAGRAM

This table shows how the pinout of the I2C Extend Click Board™ corresponds to the pinout on the mikroBUS™ socket (the latter shown in the two middle columns).

Notes	Pin					Pin	Notes
NC	1	AN	PWM	16	NC
Reset pin	RST	2	RST	INT	15	INT	Interrupt pin
SPI Chip Select	CS	3	CS	RX	14	NC
NC	4	SCK	TX	13	NC
NC	5	MISO	SCL	12	SCL	I2C Clock
NC	6	MOSI	SDA	11	SDA	I2C Data
Power Supply	3.3V	7	3.3V	5V	10	5V	Power Supply
Ground	GND	8	GND	GND	9	GND	Ground

ONBOARD SETTINGS AND INDICATORS

I2C EXTEND CLICK ELECTRICAL SPECIFICATIONS