< 3/86>VDP2 User's Manual/1.3 Scroll function

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★ HARDWARE Manual ★ VDP2 User's Manual ★ Chapter 1 VDP2 Functions

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VDP2 User's Manual/Chapter

■1.3 Scroll function

VDP2's scrolling features include scrolling screens and windows.

●Display screen

TV screen modes include:

Table 1.1 TV screen mode

TV screen mode	graphic mode	horizontal resolution (pixel)	vertical resolution (pixel)	display device
normal	normal Graphic A	320	224 240 256 selectable from	NTSC method or PAL TV
normal	normal Graphic B	352
high resolution	high resolution Graphic A	640
high resolution	high resolution Graphic B	704
dedicated monitor	dedicated normal Graphic A	320	480	31kHz monitor
	dedicated normal Graphic B	352	480	HD monitor
	Dedicated high resolution Graphic A	640	480	31kHz monitor
	Dedicated high resolution Graphic B	704	480	HD monitor

The scroll screens that can be displayed include the following.

Table 1.2 Scroll screen

scroll screen name		name	remarks
normal scroll screen	Normal scroll 0	NBG0	Can be moved up/down/left/right and enlarged/reduced
	normal scroll 1	NBG1	Can be moved up/down/left/right and enlarged/reduced
	normal scroll 2	NBG2	Can move up/down/left/right
	normal scroll 3	NBG3	Can move up/down/left/right
rotating scroll screen	rotation scroll 0	RBG0	Can be scaled and rotated
rotating scroll screen	rotating scroll 1	RBG1	Can be scaled and rotated
line screen	line color screen	LNCL	Used only for color calculations
line screen	back screen	BACK	Displayed only when no other screens are displayed
extended screen	External input screen	EXBG	Screen input from outside

The windows include:

Table 1.3 Window

window name	name	remarks
normal window	W0	Can be made into a line window
normal window	W1	Can be made into a line window
sprite window	SW	Window with sprite character

●Scroll screen

The functions of the scroll screen are as follows.

Table 1.4 Scroll screen functions

function	Normal scroll screen				rotating scroll screen
function	NBG0	NBG1	NBG2	NBG3	RBG0	RBG1
Number of character colors	16 colors 256 colors 2048 colors * 32768 colors 16.77 million colors more selection	16 colors 256 colors 2048 colors * 32768 colors more selection	16 colors 256 colors more selection	16 colors 256 colors more selection	16 colors 256 colors 2048 colors * 32768 colors 16.77 million colors more selection	16 colors 256 colors 2048 colors * 32768 colors 16.77 million colors more selection
character size	Select from 1 cell horizontally x 1 cell vertically or 2 cells horizontally x 2 cells vertically.
pattern name Data size	Select from 1 word or 2 words
plain size	Select from 1 page wide x 1 page tall, 2 pages wide x 1 page tall, or 2 pages wide x 2 pages tall.
Number of planes	4	4	4	4	16	16
Bitmap display	It can be displayed	It can be displayed	Not displayable	Not displayable	It can be displayed	Not displayable
bitmap size	512 horizontal dots x 256 vertical dots 512 dots horizontally x 512 dots vertically 1024 dots horizontally x 256 dots vertically 1024 dots horizontally x 512 dots vertically more selection		none		Width 512 x height 256 dots Width 512 x height 512 dots more selection	none
Scaling function	1/4x to 256x		none		Possible at any magnification
Rotation function	none				can be
line Scroll function	can be	can be	none	none	none
vertical cell Scroll function	can be	can be	none	none	none
Mosaic processing function	can be				Yes (horizontal direction only)

[Note] In * , 2048 colors are when the color RAM mode is mode 1, and mode 0 or 2.
In this case, there will be 1024 colors.

If only one rotating scroll screen is displayed, the normal scroll screen can also be displayed at the same time, but if two rotating scroll screens are displayed, the normal scroll screen cannot be displayed at all. At this time, the register for RBG1 is used for NBG0.
When the external input screen is displayed, NBG1 cannot be displayed. At this time, the register for NBG1 is used to set the external input screen.

●Line screen

The line color screen is a screen for performing color calculations with other screens. You can make the entire screen a solid color or specify a color for each line, but you cannot display characters.
The back screen is the screen that appears when all other screens are transparent. You can make the entire screen a solid color or specify a color for each line, but you cannot display characters.

●Window

For the normal window, you can choose between a normal rectangular window, which is specified by two screen coordinates at the top left and bottom right, and a normal line window, where the left and right screen coordinates are specified for each line. A sprite window is a window containing sprite characters.
Depending on the purpose of use, the window has a ``transparency processing window'' that specifies areas to be made transparent, a ``color calculation window'' that specifies areas that will not perform color calculations, and a ``rotation parameter window'' that allows you to switch screens using two rotation parameters. There are 3 types:
The windows to be used for each screen and how they are stacked can be specified for each screen.

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★ HARDWARE Manual ★ VDP2 User's Manual ★ Chapter 1 VDP2 Functions