Browse Prior Art Database

Character Generator Memory

IP.com Disclosure Number: IPCOM000047240D
Original Publication Date: 1983-Oct-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Dewanz, DM: AUTHOR [+2]

Abstract

This structure provides a character generator memory for a CRT display including means generating a standard character set and special characters depending on different character set conventions. Partitioning of the memory array reduces the chip area required by conventional character generators. The memory array is partitioned as shown in the figure, the special characters (e.g., a total of 87 characters) are stored in the left half and the standard characters (e.g., the 256-EBCDIC character set) are stored in the right half. Each word line in the array corresponds to a single 8 X 11-dot character. Four address lines feed a conventional bit decoder to select one out of 11 groups of 8 bits. Eight address lines feed a conventional word decoder to provide a selected one of the 256-EBCDIC characters.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 81% of the total text.

Page 1 of 2

Character Generator Memory

This structure provides a character generator memory for a CRT display including means generating a standard character set and special characters depending on different character set conventions. Partitioning of the memory array reduces the chip area required by conventional character generators. The memory array is partitioned as shown in the figure, the special characters (e.g., a total of 87 characters) are stored in the left half and the standard characters (e.g., the 256-EBCDIC character set) are stored in the right half. Each word line in the array corresponds to a single 8 X 11-dot character. Four address lines feed a conventional bit decoder to select one out of 11 groups of 8 bits. Eight address lines feed a conventional word decoder to provide a selected one of the 256- EBCDIC characters. The same eight address lines and four additional address lines that designate the special character code feed the input decoders to provide a selected one of the 87 special characters. During a character generation access, the 16 addresses are gated to the respective word and bit decoders. If a special character is addressed, one of the 87 special character decoders will be selected, thereby driving the respective word line high and generating an INHIBIT signal to disable the one-of-256 word decoders. If a standard character is addressed, all 87 word decoders will be deselected. This deselection will cause an ACTIVATE signal to be generated....