I2C Serial Port Adapter & Extender

Jaakko Ala-Paavola

Status: Draft



I2C bus was originally designed by Philips for Inter-IC (I2C) communication. The bus has two signals: data & clock, and it's often called two-wire interface (TWI). The are plenty of ICs (microcontrollers, EEPROMs, sensors, etc.) equiped with the interface on the market. Even most of industry standard PC motherboards are equiped with bus, and it's well supported by many OSs (especially linux).

However there are few drawbacks in using the I2C:

The focus of this project is to create a low-cost solution for both of this problems.

I2C Serial port Adapter


Simple I2C Serial port adapter.


i2c-serial.c Simple serial port adapter module for linux I2C driver (see documentation).
Adapter uses following serial port hand-shaking signals:

I2C extender


Serial port adapter with RS-485 extender.

I2C extender (I2C-RS485 adapter).

External resources