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★ HARDWARE Manual ★ VDP2 User's Manual ★ Chapter 4 Scroll screen
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VDP2 User's Manual/Chapter 4 Scroll screen

■4.11 Mosaic processing

Mosaic processing can be performed on each scroll screen, and the mosaic size can be set for both the horizontal and vertical directions.
Mosaic processing is a function that divides each scroll screen into several areas of a specified size and displays the color of the upper left dot of each area on all dots within that area. A mosaic pattern is obtained by lining up areas of different colors. The size of the mosaic area can be specified independently in the horizontal and vertical directions. The horizontal size can be specified in 1-dot increments from 1 to 16 dots. The vertical size can be specified from 1 to 16 dots in 1-dot increments in non-interlace mode, and from 2 to 32 dots in 2-dot increments in interlace mode. Setting a register to perform mosaic processing when in double-dense interlaced mode forces the screen to display in single-dense interlaced mode.
If you perform mosaic processing on NBG0 or NBG1, the vertical cell scrolling function will no longer be available. Also, mosaic processing for RBG0 and RBG1 can only be performed in the horizontal direction.
The mosaic pattern is shown in Figure 4.19.

Figure 4.19 Mosaic pattern

●Mosaic control register

The mosaic control register specifies whether to perform mosaic processing. This is a 16-bit write-only register located at address 180022H. The value is cleared to 0 after power-on or reset, so be sure to set it.

MZCTL 180022H
   15   
   14   
   13   
   12   
   11   
   10   
   09   
   08   
 MZSZV3
 MZSZV2
 MZSZV1
 MZSZV0
 MZSZH3
 MZSZH2
 MZSZH1
 MZSZH0

   07   
   06   
   05   
   04   
   03   
   02   
   01   
   00   
 -
 -
 -
 R0MZE
 N3MZE
 N2MZE
 N1MZE
 N0MZE

　　
Mosaic size bit (MZSZV3〜MZSZV0, MZSZH3〜MZSZH0)
Specify the horizontal and vertical mosaic size.

MZSZV3～MZSZV0 180022H bits 15-12 For vertical mosaic size
MZSZH3～MZSZH0 180022H bits 11-8 For horizontal mosaic size

MZSZV3 MZSZV2 MZSZV1 MZSZV0 Vertical mosaic size
non-interlaced interlace
 0
 0
 0
 0
 1 dot 2 dots
 0
 0
 0
 1
 2 dots 4 dots
 0
 0
 1
 0
 3 dots 6 dots
 0
 0
 1
 1
 4 dots 8 dots
 0
 1
 0
 0
 5 dots 10 dots
 0
 1
 0
 1
 6 dots 12 dots
 0
 1
 1
 0
 7 dots 14 dots
 0
 1
 1
 1
 8 dots 16 dots
 1
 0
 0
 0
 9 dots 18 dots
 1
 0
 0
 1
 10 dots 20 dots
 1
 0
 1
 0
 11 dots 22 dots
 1
 0
 1
 1
 12 dots 24 dots
 1
 1
 0
 0
 13 dots 26 dots
 1
 1
 0
 1
 14 dots 28 dots
 1
 1
 1
 0
 15 dots 30 dots
 1
 1
 1
 1
 16 dots 32 dots

MZSZH3 MZSZH2 MZSZH1 MZSZH0 horizontal mosaic size
 0
 0
 0
 0
 1 dot
 0
 0
 0
 1
 2 dots
 0
 0
 1
 0
 3 dots
 0
 0
 1
 1
 4 dots
 0
 1
 0
 0
 5 dots
 0
 1
 0
 1
 6 dots
 0
 1
 1
 0
 7 dots
 0
 1
 1
 1
 8 dots
 1
 0
 0
 0
 9 dots
 1
 0
 0
 1
 10 dots
 1
 0
 1
 0
 11 dots
 1
 0
 1
 1
 12 dots
 1
 1
 0
 0
 13 dots
 1
 1
 0
 1
 14 dots
 1
 1
 1
 0
 15 dots
 1
 1
 1
 1
 16 dots
[Note] This is not related to interlace settings.

　　　　　

Mosaic enable bit (N0MZE, N1MZE, N2MZE, N3MZE, R0MZE)
Specify the screen to perform mosaic processing.

N0MZE 180022H bit 0 For NBG0 (or for RBG1)
N1MZE 180022H bit 1 For NBG1
N2MZE 180022H bit 2 For NBG2
N3MZE 180022H bit 3 For NBG3
R0MZE 180022H bit 4 For RBG0

xxMZE process
 0
 No mosaic processing
 1
 Perform mosaic processing
[Note] xx in the bit name is N0, N1, N2, N3, or R0.

When mosaicking a rotating scroll surface, only horizontal mosaicking occurs.
If you perform mosaic processing in double-dense interlace mode, the screen will be forced to display in single-dense interlace mode.
If you perform mosaic processing on NBG0 or NBG1, you will not be able to use the vertical cell scroll function on the mosaiced screen. Therefore, the display screen at that time will be a mosaic version of the screen without vertical cell scrolling.

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★ HARDWARE Manual VDP2 User's Manual ★ Chapter 4 Scroll screen
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