Browse Prior Art Database

MICROPROCESSOR DATA DISPLAY SYSTEM

IP.com Disclosure Number: IPCOM000024806D
Original Publication Date: 1982-Apr-30
Included in the Prior Art Database: 2004-Apr-04
Document File: 2 page(s) / 140K

Publishing Venue

Xerox Disclosure Journal

Abstract

In the past, liquid crystal display systems have been driven by the logic generated by hard wired components. These include gates, shift registers, and both randomly accessed and read-only memories. However, as liquid crystal displays become larger and the logic becomes more complex, the possibility of interlaced scanning of a matrix display must be allowed for as well as the task of slowing data entry during the introduction of new data while maintaining a high rate of scan and refreshing old data. Also, various pulse modulation modes may be used. The pattern of connecting wires to the display may not, however, be the most convenient for implementing these additional features with the requirement that interconnecting leads in the hard wired logic be switched or changed around and the need for additional gates, registers and wiring.

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XEROX DISCLOSURE JOURNAL

MICROPROCESSOR DATA DISPLAY SYSTEM
Joseph F. Stephany

Proposed Classification
U.S. C1. 340/336 Int. C1. G08b 1/00

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FIG. I

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ABCD

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FIG. 2 J3

In the past, liquid crystal display systems have been driven by the logic generated by hard wired components. These include gates, shift registers, and both randomly accessed and read-only memories. However, as liquid crystal displays become larger and the logic becomes more complex, the possibility of interlaced scanning of a matrix display must be allowed for as well as the task of slowing data entry during the introduction of new data while maintaining a high rate of scan and refreshing old data. Also, various pulse modulation modes may be used. The pattern of connecting wires to the display may not, however, be the most convenient for implementing these additional features with the requirement that interconnecting leads in the hard wired logic be switched or changed around and the need for additional gates, registers and wiring.

It is proposed that the multitude of gates, registers and wires be replaced with a single microprocessor, a single shift register, a single decoder and a suitable set of

Volume 7 Number 2 March/April 1982 77

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MICROPROCESSOR DATA DISPLAY SYSTEM (Cont'd)

drivers. The low cost of the microprocessor and the associated components combined with the ease of fabricating a few components onto a board makes this an attractive approach as compared with the system in which individual com- ponents are used.

As shown in Figure 1, a microprocessor 5 is connected to a PIA (Peripheral Interface Adapter) board 6. Board 6 typicaly has an output of 32 latched bits even though microprocessor 5 has 8 bit data words. Sixteen of these bits are shifted to serial form by a 16 bit shift register 8 and are transferred to a control shift register 9 for liquid crystal display 10. Another 3 bits from the PIA board 6 are input to 1/N decoder 12 to select the line being displayed by liquid crystal display
10. Clock pulses output by clock 11 synchronize the system with one bit used as a load pulse to the 16 bit parallel to serial shift register 8.

A schematic of the necessary software is shown in Figure 2. A bit pattern of the displayed image is placed between locations M(a) to M(b) of display image memory
13. A scan program 14 lifts 16 bits of information in these memory locations and transfe...