★ 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 the scroll surface for each screen, and the mosaic size at that time can be set for each of 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 dot on the upper left of each area on all the dots in that area. You can get a mosaic pattern by arranging areas of different colors. The size of the mosaic area can be specified horizontally and vertically independently. The horizontal size can be specified from 1 to 16 dots in 1-dot increments. The vertical size can be specified from 1 to 16 dots in 1-dot increments in non-interlaced mode, and from 2 to 32 dots in 2-dot increments in interlaced mode. Setting the register for mosaicking in double-dense interlaced mode forces the screen to appear in single-dense interlaced mode.
If mosaic processing is performed on NBG0 or NBG1, the vertical cell scroll function cannot be used. Also, RBG0 and RBG1 mosaic processing can only be done 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. A write-only 16-bit register located at address 180022H. After turning on the power or resetting, the value will be cleared to 0, so be sure to set it.

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

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

　　
Mosaic size bit : Mosaic size bit (MZSZV3 to MZSZV0, MZSZH3 to MZSZH0)
Specifies 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] It has nothing to do with the interlace setting.

　　　　　

Mosaic enable bit : 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
 Does not perform mosaic processing
 1
 Perform mosaic processing
Note The bit name xx can be N0, N1, N2, N3, or R0.

When mosaicking a rotating scroll plane, only horizontal mosaicking is performed.
If mosaic processing is performed in the double-dense interlaced mode, the screen is forcibly displayed in the single-dense interlaced mode.
If mosaic processing is performed on NBG0 or NBG1, the vertical cell scroll function cannot be used on the mosaic processed screen. Therefore, the display screen at that time will be the one in which mosaic processing is performed on the screen when vertical cell scrolling is not performed.

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