PCF8579 LCD Column Driver for Dot Matrix Graphic Displays

PCF879 forms part of a chip capable of driving up to 40960 dots used in conjunction with the PCF8578 LCD row/column driver. The PCF8579 is a low power CMOS LCD 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 and can drive 32 x 40 dots in a 32 row multiplexed LCD. Up to 16 PCF8579 can be cascaded and up to 32 devices may be used on the same I²C-bus (using the two slave addresses). Together these devices form a general purpose LCD dot matrix driver chip set, capable of driving displays of up to 40960 dots. The PCF8579 is compatible with most microcontrollers and communicates via a two-line bidirectional bus (I²C-bus). To allow partial VDD shutdown the ESD protection system of the SCL and SDA pins does not use a diode connected to VDD. Communication overhead is minimized by a display RAM with auto-incremented addressing and display bank switching.

Block Diagram

Block Diagram

Why Used

  • 1280-bit RAM for display data storage
  • 40 column outputs
  • LDC column driver
  • Selectable multiplex rate multiplex; 1:8, 1:16, 1:24 or 1:32
  • Externally selectable bias configuration, 5 or 6 levels

Where Used

  • Point-of-Sales (PoS) terminals
  • Industrial computer terminals
  • Automotive information systems
  • Telecommunication systems
  • Instrumentation

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