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Addressing Method for Diagonal Grid Non-Interlace Raster-Scanned Images

IP.com Disclosure Number: IPCOM000036336D
Original Publication Date: 1989-Sep-01
Included in the Prior Art Database: 2005-Jan-28
Document File: 3 page(s) / 75K

Publishing Venue

IBM

Related People

Flurry, GA: AUTHOR [+2]

Abstract

This addressing method allows a diagonal grid (DG) formatted image to be stored with other more conventional square grid array formatted images. This method requires little additional hardware to support.

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Addressing Method for Diagonal Grid Non-Interlace Raster-Scanned Images

This addressing method allows a diagonal grid (DG) formatted image to be stored with other more conventional square grid array formatted images. This method requires little additional hardware to support.

As designated by the '*' in Fig. 1, all odd counts of the scan

(Image Omitted)

line address require that a row address for memory unit 0 be incremented by one from the row address for memory unit 1 and that the addresses on all even counts be the same for both of the memory units.

Fig. 2 shows the additional addressing logic to support the DG addressing method shown in Fig. 1. Blocks #1 and #2 in Fig. 2 produce conventional horizontal and vertical timing for a raster scan CRT. Each horizontal blanking period the scan line address (block #2) is incremented, producing an incremental count as shown in Fig. 1. During the blanking period the new scan line information must be loaded into the secondary ports of the video DRAMs. This is accomplished by a sequence produced from the state machine (block #4) which is triggered each horizontal sync from the horizontal timer (block #1). The sequence produced from the state machine causes a special memory cycle (shift register load cycle).

The address for the shift register load cycle is produce by blocks #2, #3, #5, #6, #7, #8, #9, and #10. Block #2 drives block #3 with the scan line address. Block #3 divides the scan line address by two and outputs the dividend and remainder to blocks #5 and #6. Block #5 increments the address by one. Block #6 passes the dividend when the remainder equals 0 (even scan line addresses) or passes the dividend p...