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Multi-purpose serial to parallel interface

The UltraSI serial interface adaptor is a general serial to parallel interface for data transfer. It is most often used in the HD44780 LCD modules, to allow them to interface with serial ports.

The UltraSI is best used when one chooses to mount an LCD module into the personal computer. Many problems can arise when using an LCD module with a parallel interface. Because operating systems such as Microsoft Windows 2000 and Microsoft Windows XP has software mechanisms to protect the parallel port from casual program access, one might face difficulty interfacing a LCD module with the PC in this operating environments. There are API softwares that attempt to bypass the parallel port protection and these software, although being able to operate the parallel port successfully, sometimes run into stability problems due to direct IO access.

A serial port is a more logical choice in interfacing an LCD module to any devices due to the fact that few IO lines are required. For the LCD to operate in a serial interface, only 2 wires (RCV and GND) are required. This results in more elegant mounting solutions. Also, a PC is able to install up to a maximum of 8 serial ports (default 2), as opposed to only 1 single parallel port in the PC. Using a serial capable LCD avoids the use of the parallel port, in the case that a more important device requires the parallel port (such as the printer).

Complete Specifications

  • RS-232 interface at 9600 Baud Rate
  • Can be soldered directly to LCD
  • Takes power input directly from 3.5" drive power connector
  • 8-bits of general purpose output for future expansion
  • Accomodates LCDs with pin configurations of :
    1x14 (2.54mm spacing)
    1x14 (2mm spacing)
    2x7 (2.54mm spacing)