By Ted Salazar, Maxim Integrated ProductsAug 8 2007 (0:07 AM), Embedded.com
The Inter IC (I2C) bus was developed by Philips Semiconductor in the early 1980s to simplify electronic products by reducing the number of parallel data lines. Version 1.0 of the I2C-Bus specification, released by Philips in 1992, defined a simple, 2-wire, bidirectional bus for communications between ICs.
By 1998, the I2C bus had become the de-facto standard for low-speed IC-to-IC communications. At that time more than 50 licensed companies were using the standard, and the I2C interface was included in more than 1000 different ICs.
Because the I2C bus is currently the industry's most widely used serial bus, it behooves a system designer to have a handful of proven implementations on hand.
The method you choose - on-chip, bit-banged, or IP-core implementation - depends mostly on the system processor, but nothing is easier than using an approach that is proven and already works. This article includes a working reference for each of the three methods.
The I2C bus configurations presented in this article have been proven to ensure easy communications with slave devices on the bus. Each implementation includes examples in the form of schematics and code.
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