General description

The PCF8578 is a low power CMOS1 LCD row and column driver, designed to drive dot matrix graphic displays at multiplex rates of 1:8, 1:16, 1:24 or 1:32. The device has 40 outputs, of which 24 are programmable and configurable for the following ratios of rows/columns: 32⁄8, 24⁄16, 16⁄24 or 8⁄32. The PCF8578 can function as a stand-alone LCD controller and driver for use in small systems. For larger systems it can be used in conjunction with up to 32 PCF8579s for which it has been optimized. Together these two devices form a general purpose LCD dot matrix driver chip set, capable of driving displays of up to 40960 dots. The PCF8578 is compatible with most microcontrollers and communicates via a two-line bidirectional bus (I2C-bus). Communication overhead is minimized by a display RAM with auto-incremented addressing and display bank switching.

Features

■ Single chip LCD controller and driver

■ Stand-alone or may be used with up to 32 PCF8579s (40960 dots possible)

■ 40 driver outputs, configurable for several ratios of rows/columns: 32⁄8, 24⁄16, 16⁄24 or 8⁄32

■ Selectable multiplex rates: 1:8, 1:16, 1:24 or 1:32

■ Externally selectable bias configuration, 5 or 6 levels

■ 1280-bit RAM for display data storage and scratch pad

■ Display memory bank switching

■ Auto-incremented data loading across hardware subaddress boundaries (with PCF8579)

■ Provides display synchronization for PCF8579

■ On-chip oscillator, requires only 1 external resistor

■ Power-On Reset (POR) blanks display

■ Logic voltage supply range 2.5 V to 6 V

■ Maximum LCD supply voltage 9 V

■ Low power consumption

■ I2C-bus interface

■ Compatible with most microcontrollers

■ Optimized pinning for single plane wiring in multiple device applications (with PCF8579)

■ Space saving 56-lead small outline package and 64 pin quad flat pack

Applications

■ Automotive information systems

■ Telecommunication systems

■ Point-of-sale terminals

■ Industrial computer terminals

■ Instrumentation