Optimized display device memory utilization

• US 4,520,358 A
• Filed: 05/11/1982
• Issued: 05/28/1985
• Est. Priority Date: 05/20/1981
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Makino, Tomoaki
• Primary Examiner(s): Curtis, Marshall M.
• Assistant Examiner(s): Kovalick, Vincent P.
• Application Number:
  US06/377,243
• Time in Patent Office: 1,113 Days
• Field of Search: 340/799, 340/703, 340/804, 340/721, 340/747, 340/750, 340/745
• US Class Current: 345/551
• CPC Class Codes: G09G 5/02 characterised by the way in which colour is displayed details of colour display specific for CRTs G09G1/28; specific for flat matrix panels other than liquid crystal displays G09G3/2003; specific for liquid crystal displays G09G3/3607
• CPC Class Codes: G09G 5/024 using colour registers, e.g. to control background, foreground, surface filling G09G5/06 takes precedence

Abstract

A method of utilizing a memory device for a display device which comprises a parallel combination of an image and a control memory connected to a decoder. At each of addresses assigned to form a color signal, the image memory stores a byte including bits corresponding to green pieces of color information alternating with bits corresponding to red pieces of color information; the control memory stores a byte including four consecutive bits corresponding to blue pieces of color information. The decoder combines associated triads of the red, green and blue bits to form a color signal for a display indicating device. At each of the addresses assigned to form a dot signal, the image memory stores a byte representing the brilliance of a dot and the control memory stores a byte including three consecutive color bits for a foreground to be displayed when a corresponding bit in the image memory is a binary "1" and another three color bits for a background to be displayed when a corresponding bit in the image memory is a binary "0".

Claims

1. In a display indicating system having a memory device including a parallel combination of an image memory and a control memory and further including a decoder which is connected to said parallel combination of said image and control memory, a method of utilizing said memory device to selectively store both color images and characters comprising the steps of:

for a pixel of a color image, storing color information in a selected address in said image memory and in selected portions of a selected address in said control memory;

for a pixel of a character, storing dot brilliance information in a selected address in said image memory;

storing a mode specifying bit in a selected portion of a selected address in said control memory, said mode specifying bit being indicative of whether its corresponding pixel is part of a color image or characters;

for a pixel of a character, storing color information in selected portions of a selected address in said control memory;

reading out data stored in a selected address in both said image and control memories and feeding said data to said decoder, said decoder decoding said data into red and green and blue data for feeding a display of said systems in accordance with the state of the mode specifying bit, wherein, for a fixed word size at a selected address in said image and control memories, said display displays a preset degree of color resolution for a color image and a preset degree of brilliance resolution for a character and further enables a variable dot resolution within a single picture displayed by said display.

2. A method as claimed in claim 1, wherein said image memory has stored at each of its first addresses assigned to form a color image pixel, eight bits including odd-numbered bits representing a first color piece of color information and even-numbered bits representing a second color piece of color information and at each of its second addresses assigned to form a dot for a character pixel, an 8-bit piece of character information representing a brilliance of a dot while said control memory has stored at each of its first addresses eight bits including four consecutive bits representing a third color piece of color information and at each of its second addresses eight bits including three consecutive bits representing three primary pieces of color information for a foreground displayed with any of the corresponding bits in said image memory having a value of binary "1" and three consecutive bits following the first-mentioned three consecutive bits and representing three primary pieces of color information for a background displayed with any of the corresponding bits in said image memory having a value of binary "0".