<53/86> VDP2 User's Manual / 8.1 Window Area

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VDP2 User's Manual / Chapter 8 Window

■ 8.1 Window area

The scroll IC window has two normal windows (W0, W1) and one sprite window (SW). The normal window is specified by the start point coordinates and end point coordinates on the TV screen, and the sprite window is specified by the value of the most significant bit of the sprite data written in the frame buffer. Each window allows you to specify which scroll screen to enable and whether to enable the inner or outer area. Also, if multiple windows are enabled, they can be overlapped with AND or OR logic.

For the normal window, you can select either a normal rectangular window specified by horizontal and vertical start and end coordinates, or a normal line window that specifies horizontal start and end coordinates for each line. For the start point coordinates and end point coordinates, the coordinate values on the TV screen are set in each register, not the coordinate values on the scroll screen.

● Normal rectangular window

A normal rectangular window can be obtained by specifying the start point coordinates of the upper left corner and the end point coordinates of the lower right corner of the window in the window position register. The area surrounded by the specified coordinates is the inside, and the other areas are the outside. The window border is considered inside.
If the start point coordinates are larger than the end point coordinates in either the horizontal or vertical direction, the entire screen is judged as the area outside the window.
A normal rectangular window is shown in Figure 8.1.

Figure 8.1 Normal rectangular window

● Window position register

The window position register specifies the horizontal and vertical start and end coordinates of the normal window. This is a write-only 16-bit register located at addresses 1800C0H to 1800CEH. After turning on the power or resetting, the value will be cleared to 0, so be sure to set it.

WPSX0 1800C0H

---	---	---	---	---	---	W0SX9	W0SX8
15	14	13	12	11	Ten	09 09	08 08

07 07
06 06
05 05
04
03 03
02 02
01 01
00
W0SX7
W0SX6
W0SX5
W0SX4
W0SX3
W0SX2
W0SX1
W0SX0

07 07	06 06	05 05	04	03 03	02 02	01 01	00
W0SX7	W0SX6	W0SX5	W0SX4	W0SX3	W0SX2	W0SX1	W0SX0

WPSY0 1800C2H

---	---	---	---	---	---	W0SY9	W0SY8
15	14	13	12	11	Ten	09 09	08 08

07 07
06 06
05 05
04
03 03
02 02
01 01
00
W0SY7
W0SY6
W0SY5
W0SY4
W0SY3
W0SY2
W0SY1
W0SY0

07 07	06 06	05 05	04	03 03	02 02	01 01	00
W0SY7	W0SY6	W0SY5	W0SY4	W0SY3	W0SY2	W0SY1	W0SY0

WPEX0 1800C4H

---	---	---	---	---	---	W0EX9	W0EX8
15	14	13	12	11	Ten	09 09	08 08

07 07
06 06
05 05
04
03 03
02 02
01 01
00
W0EX7
W0EX6
W0EX5
W0EX4
W0EX3
W0EX2
W0EX1
W0EX0

07 07	06 06	05 05	04	03 03	02 02	01 01	00
W0EX7	W0EX6	W0EX5	W0EX4	W0EX3	W0EX2	W0EX1	W0EX0

WPEY0 1800C6H

---	---	---	---	---	---	W0EY9	W0EY8
15	14	13	12	11	Ten	09 09	08 08

07 07
06 06
05 05
04
03 03
02 02
01 01
00
W0EY7
W0EY6
W0EY5
W0EY4
W0EY3
W0EY2
W0EY1
W0EY0

07 07	06 06	05 05	04	03 03	02 02	01 01	00
W0EY7	W0EY6	W0EY5	W0EY4	W0EY3	W0EY2	W0EY1	W0EY0

WPSX1 1800C8H

---	---	---	---	---	---	W1SX9	W1SX8
15	14	13	12	11	Ten	09 09	08 08

07 07
06 06
05 05
04
03 03
02 02
01 01
00
W1SX7
W1SX6
W1SX5
W1SX4
W1SX3
W1SX2
W1SX1
W1SX0

07 07	06 06	05 05	04	03 03	02 02	01 01	00
W1SX7	W1SX6	W1SX5	W1SX4	W1SX3	W1SX2	W1SX1	W1SX0

WPSY1 1800CAH

---	---	---	---	---	---	W1SY9	W1SY8
15	14	13	12	11	Ten	09 09	08 08

07 07
06 06
05 05
04
03 03
02 02
01 01
00
W1SY7
W1SY6
W1SY5
W1SY4
W1SY3
W1SY2
W1SY1
W1SY0

07 07	06 06	05 05	04	03 03	02 02	01 01	00
W1SY7	W1SY6	W1SY5	W1SY4	W1SY3	W1SY2	W1SY1	W1SY0

WPEX1 1800CCH

---	---	---	---	---	---	W1EX9	W1EX8
15	14	13	12	11	Ten	09 09	08 08

07 07
06 06
05 05
04
03 03
02 02
01 01
00
W1EX7
W1EX6
W1EX5
W1EX4
W1EX3
W1EX2
W1EX1
W1EX0

07 07	06 06	05 05	04	03 03	02 02	01 01	00
W1EX7	W1EX6	W1EX5	W1EX4	W1EX3	W1EX2	W1EX1	W1EX0

WPEY1 1800CEH

---	---	---	---	---	---	W1EY9	W1EY8
15	14	13	12	11	Ten	09 09	08 08

07 07
06 06
05 05
04
03 03
02 02
01 01
00
W1EY7
W1EY6
W1EY5
W1EY4
W1EY3
W1EY2
W1EY1
W1EY0

Window position bit (for horizontal coordinates) : Window start / end X bit

07 07	06 06	05 05	04	03 03	02 02	01 01	00
W1EY7	W1EY6	W1EY5	W1EY4	W1EY3	W1EY2	W1EY1	W1EY0

(W0SX9 to W0SX0, W0EX9 to W0EX0, W1SX9 to W1SX0, W1EX9 to W1EX0)
Specify the horizontal start and end coordinates. The coordinate value to be specified is the coordinate value (H counter value) on the TV screen.

W0SX9 to W0SX0	1800C0H	Bits 9-0	For W0 start point coordinates
W0EX9 ~ W0EX0	1800C4H	Bits 9-0	For W0 end point coordinates
W1SX9 to W1SX0	1800C8H	Bits 9-0	For W1 start point coordinates
W1EX9 ~ W1EX0	1800CCH	Bits 9-0	For W1 end point coordinates

The bit configuration of the register changes depending on the graphic mode setting. In the case of normal graphics, the least significant bit is invalid data. In the case of a dedicated normal graphic, the most significant bit is invalid data. Also, in the case of dedicated high-resolution graphics, the most significant bit is invalid data, and since there is no bit for H0, the value is in units of 2 pixels.
Table 8.1 shows the bit contents of the window position register depending on the graphic mode setting.

Table 8.1 Bit contents of window position register for horizontal coordinates

Graphic mode	WxxX9	WxxX8	WxxX7	WxxX6	WxxX5	WxxX4	WxxX3	WxxX2	WxxX1	WxxX0
normal	H8	H7	H6	H5	H4	H3	H2	H1	H0	invalid
High resolution	H9	H8	H7	H6	H5	H4	H3	H2	H1	H0
Dedicated normal	invalid	H8	H7	H6	H5	H4	H3	H2	H1	H0
Dedicated high resolution	invalid	H9	H8	H7	H6	H5	H4	H3	H2	H1

Note The bit name xx can be 0S, 0E, 1S, or 1E.

Window position bit (for vertical coordinates) : Window start / end Y bit

(W0SY8 ~ W0SY0, W0EY8 ~ W0EY0, W1SY8 ~ W1SY0, W1EY8 ~ W1EY0)
Specify the vertical start and end coordinates. The coordinate value to be specified is the coordinate value (V counter value) on the TV screen.

W0SY8 to W0SY0	1800C2H	Bits 8-0	For W0 start point coordinates
W0EY8 ~ W0EY0	1800C6H	Bits 8-0	For W0 end point coordinates
W1SY8 to W1SY0	1800CAH	Bits 8-0	For W1 start point coordinates
W1EY8 ~ W1EY0	1800CEH	Bits 8-0	For W1 end point coordinates

The register bit configuration changes depending on the screen mode setting. For single-dense interlacing in normal and high-resolution modes, specify the V counter value for each of the even and odd fields. For double-dense interlace in normal and high-resolution modes, the least significant bit is disabled and the remaining bits specify the V counter value for each field.
Table 8.2 shows the bit contents of the window position register depending on the screen mode setting.

Table 8.2 Bit contents of window position register for vertical coordinates

TV screen (interlaced) mode	WxxY8	WxxY7	WxxY6	WxxY5	WxxY4	WxxY3	WxxY2	WxxY1	WxxY0
Normal, high resolution (non-interlaced, (Single dense interlace)	V8	V7	V6	V5	V4	V3	V2	V1	V0
Normal, high resolution (double dense interlace)	V7	V6	V5	V4	V3	V2	V1	V0	invalid
Dedicated monitor	V8	V7	V6	V5	V4	V3	V2	V1	V0

Note The bit name xx can be 0S, 0E, 1S, or 1E.

Window position Vertical end point coordinate value limit

When using a normal window in double-dense interlaced mode, do not set the value of the vertical end point coordinate window position register (WPEY0: 1800C6H, WPEY: 1800CEH) to "1FCH to 1FFH".
Entering these values disables the window.

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