i2c interface to USB interface

Posted on Feb 19, 2013

The i2c-tiny-usb project is an open source/open hardware project. The goal of i2c-tiny-usb is to provide a cheap generic i2c interface to be attached to the usb. It is meant as a replacement for those simple and cheap printer port to i2c adapters. A USB solution has several advantages incl. the built-in power supply and a more future proof interface. Furthermore no cpu intense bitbanging is required on the host side. This USB solution even requires less parts than some printer port solutions. While the i2c-tiny-usb was developed under and for Linux it also works under Windows and MacOS X. A windows demo driver and demo application is included to get you started immediately.

Click here to download the full size of the above Circuit.

The i2c-tiny-usb project is based on: The Linux USB project and the Linux i2c implementation The windows driver and test application are based on the libusb-win32 AVR-USB, a pure software implementation of USB for the AVR platform USBtiny, another software usb implementation for the AVR The USB interface of the i2c-tiny-usb interface is based on a pure software implementation and uses two pins of the AVR (PB0 and PB2). This software implementation supports low speed USB only which is signalled to the PC by resistor R1. The I2C interface is implemented using a bitbanging approach. The hardware supported twi interface of the attiny45 is bound to hardware pins at the chip that are required for USB operation and can thus not be used for I2C. The bitbanging I2C interface being used instead may not be fully I2C compatible and thus not every I2C client chip may function correctly at this bus. No incompatibilities have been reported so far. The i2c-tiny-usb provides a software adjustable i2c clock delay allowing to configure the i2c clock. The default delay is 10us. Due to additional delays in the i2c bitbanging code this results in a i2c clock of about 50kHz. For simplicity reasons all USB transfers are done via the control endpoint. Since the avr usb library does only support low speed devices it cannot use bulk transfers which are specified for high and full speed devices only. Low speed devices support so called...

Visit page

Leave Comment

characters left:

Related Circuits

USB powered LED

This is a simple LED circuit that takes power from the USB port. I needed this USB light since long time ago but, finally; I was able to build it. The circuit schematic is so simple: Just one...

New Circuits

Zero consumption Anti-theft High power Code Switch for E-Bike Batteries

This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
Ultrasonic distance finder circuit

The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Simple Metal detector circuit with CD4030

Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Fully automatic watering circuit for flower pots

Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
Simple deep searching metal detector circuit

The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
Sub-Harmonic Bass Converter for Electric Guitars

The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
Echo Depth Sounding Sonar for Boats

In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
100W HiFi Audio Amplifier Circuit

This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
Plant-Pot Water Level Indicator Circuit

A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....