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Semi-Graphics on Character Display

IP.com Disclosure Number: IPCOM000049017D
Original Publication Date: 1982-Apr-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 2 page(s) / 60K

Publishing Venue

IBM

Related People

Yashiro, M: AUTHOR [+2]

Abstract

A technique is described for generating semi-graphics on a conventional character display with a regenerate buffer RAM (random-access memory) of storage capacity to store coded data for characters for one display screen. In semi-graphic mode, a character box is divided into equal semi-graphic elements which are turned on independently by data bits in the regenerate buffer. The semi-graphic mode is in particular useful to simulate a full page text on the character display with each semi-graphic element simulating one character. Character and semi-graphic modes can co-exist on the same screen.

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Semi-Graphics on Character Display

A technique is described for generating semi-graphics on a conventional character display with a regenerate buffer RAM (random-access memory) of storage capacity to store coded data for characters for one display screen. In semi-graphic mode, a character box is divided into equal semi-graphic elements which are turned on independently by data bits in the regenerate buffer. The semi-graphic mode is in particular useful to simulate a full page text on the character display with each semi-graphic element simulating one character. Character and semi-graphic modes can co-exist on the same screen.

Referring to Fig. 3, a regenerate buffer RAM 10 has 16 bit positions for each character box. In character mode, eight out of the 16 bit positions are used to store a character code and the remaining positions are used for control bits. Each character is displayed in a character box of 9 x 16 dots, as shown in Fig. 1. In semi-graphic mode, the character box is divided into 12 semi-graphic elements of 3 x 4 dots, as indicated by broken lines in Fig. 2, and 2 x 2 dots of each element A1, A2. A3 - - - D1, D2, D3 are selectively lighted. Twelve of the 16 bit positions are used to store data bits to control lighting of the 12 elements, with each bit controlling a corresponding one of the elements. Switching between character and semi-graphic modes is performed by detecting special patterns stored in the regenerate buffer 10. A special pattern occupies one character position in the regenerate buffer and is displayed as a blank on the screen. A field between tw...