The I2C bus, also known as inter-IC bus, is a bidirectional, two-wire, multi-user bus, as shown in Fig. 1. It was developed by Philips Semiconductors (1) to connect micro controllers, EEPROMs, A/D and D/A converters, I/O interfaces, and other peripherals. The I2C bus consists of two lines: a serial data line (SDA) and a serial clock line (SCL). This serial bus has a data transfer rate of up to 100 kBit/s in the standard mode, up to 400 kBit/s in the fast mode, and up to MBit/s in the fast mode plus. The 3.4 MBit/s high speed mode and the 5 MBit/s ultra fast mode are not considered in this application note, because they require either current-source pull-up circuits or are uni-directional.
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