Control device for writing for multi-window display

• US 4,769,762 A
• Filed: 02/14/1986
• Issued: 09/06/1988
• Est. Priority Date: 02/18/1985
• Status: Expired due to Term

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Tsujido, Yoshinori
• Primary Examiner(s): Shaw, Gareth D.
• Assistant Examiner(s): Kriess, Kevin A.
• Application Number:
  US06/829,225
• Time in Patent Office: 935 Days
• Field of Search: 364/521, 364/518, 364/200 MS File, 364/900 MS File, 340/721, 340/716, 340/717, 340/750, 340/800, 340/801, 340/803
• US Class Current: 715/807
• CPC Class Codes: G09G 5/14 Display of multiple viewports

Abstract

In a control device for writing data for a multi-window display system having a function to simultaneously display a plurality of pictures on a display surface, there are provided a write controlling mapping buffer storing at corresponding addresses numbers of window display regions for the data to be written into a display frame memory, and a window identification number register provided with a window identification number for the data to be written. The data can be written into the display frame memory only when output of the write controlling mapping buffer and output of the window identification number register agree with each other.

Claims

1. In a control device for writing for a multi-window display system including display controlling means and a display frame memory, wherein, in a write cycle, data is written into said display frame memory according to an address signal supplied from said display controller means, and, in a display cycle, the data which is stored at the address specified by the address signal supplied from said display controller means is output, said control device further comprising:

a write controlling mapping buffer for storing regional data about window display regions at corresponding addresses for the data to be written into said display frame memory and for outputting a corresponding window identifying number when said display controlling means outputs an address during a write cycle;

a window identification number register with a window identification number set therein corresponding to the data to be written into said display frame memory; and

a coincidence detection circuit receiving the window identifying number from said write controlling mapping buffer corresponding to the address for the data to be written thereat and receiving the window identification number from said window identification number register for supplying, only when a coincidence between these two input window identification numbers is detected, said display frame memory with a signal allowing the data to be written in said frame memory.

2. A control device as claimed in claim 1 wherein said display controlling means includes a display controller.

3. A control device as claimed in claim 1 wherein said display controlling means includes a CPU.