Overview
The VSC055 Enhanced I2C Backplane Controller is an integrated CMOS circuit that significantly reduces system cost by integrating all of the digital logic typically required to monitor a storage enclosure. The VSC055 may be used in any embedded control application including parallel SCSI, Fibre Channel or any other application where the monitoring and control of a large number of digital I/O signals is required. Programming the VSC055 is easy through a convenient programming model, which reduces the overall duration of the design-in cycle. Data is read and written to the device over an addressable (3-bit) I2C serial interface, allowing multiple VSC055 devices on a single two-wire bus.

Device Features
 • Up to 64 bits of user-definable, bi-directional general purpose I/O (5 volt tolerant)
 • Slave mode I2C serial interface
 • Integrated Port Bypass, Clock Recovery and Signal Detect support for up to 16 drives
 • Eight programmable fan speed monitoring inputs
 • Eight programmable pulse width modulated fan control outputs
 • Pairing of GPI/O pins for direct input/output signal routing/buffering
 • Two clock input ranges: 8 to 10MHz (crystal) or 8.0 to 53.125MHz (oscillator)
 • Automatic synchronization control between multiple devices
 • Selectable direct LED drive flashing capability
 • Pin-programmable addressing for up to 16 devices on a single serial bus
 • 100 PQFP Package