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

■ 4.5 Character control register

The character control register selects the cell format and bitmap format, specifies the number of character (bitmap) colors, and specifies the character pattern or bitmap size. This is a write-only 16-bit register located at addresses 180028H to 18002AH. After turning on the power or resetting, the value will be cleared to 0, so be sure to set it.

CHCTLA 180028H
 15
 14
 13
 12
 11
 Ten
 09 09
 08 08
 ---
 ---
 N1CHCN1
 N1CHCN0
 N1BMSZ1
 N1BMSZ0
 N1BMEN
 N1CHSZ

 07 07
 06 06
 05 05
 04
 03 03
 02 02
 01 01
 00
 ---
 N0CHCN2
 N0CHCN1
 N0CHCN0
 N0BMSZ1
 N0BMSZ0
 N0BMEN
 N0CHSZ

　

CHCTLB 18002AH
 15
 14
 13
 12
 11
 Ten
 09 09
 08 08
 ---
 R0CHCN2
 R0CHCN1
 R0CHCN0
 ---
 R0BMSZ
 R0BMEN
 R0CHSZ

 07 07
 06 06
 05 05
 04
 03 03
 02 02
 01 01
 00
 ---
 ---
 N3CHCN
 N3CHSZ
 ---
 ---
 N2CHCN
 N2CHSZ

　　　　　　

Character Irosu bit: Character color number bit
(N0CHCN2 to N0CHCN0, N1CHCN1, N1CHCN0, N2CHCN, N3CHCN, R0CHCN2 to R0CHCN0)
Specify the number of character colors on each screen. When displaying in bitmap format, specify the number of bitmap colors.

 N0CHCN2 to N0CHCN0
 180028H
 Bits 6-4
 For NBG0 (or for RBG1)
 N1CHCN1, N1CHCN0
 180028H
 Bits 13, 12
 For NBG1 (or for EXBG)
 N2CHCN
 18002AH
 Bit 1
 For NBG2
 N3CHCN
 18002AH
 Bit 5
 For NBG3
 R0CHCN2 to R0CHCN0
 18002AH
 Bits 14-12
 For RBG0

 N0CHCN2
 N0CHCN1
 N0CHCN0
 TV screen mode
 Color format
 normal
 High resolution
 Dedicated monitor
 0
 0
 0
 16 colors
 16 colors
 16 colors
 Palette format
 0
 0
 1
 256 colors
 256 colors
 256 colors
 Palette format
 0
 1
 0
 2048 colors
 2048 colors
 2048 colors
 Palette format
 0
 1
 1
 32768 colors
 32768 colors
 32768 colors
 RGB format
 1
 0
 0
 16.77 million colors
 Setting prohibited
 Setting prohibited
 RGB format
 1
 0
 1
 Setting prohibited (do not set)
 1
 1
 0
 Setting prohibited (do not set)
 1
 1
 1
 Setting prohibited (do not set)
[Note] When used as RBG1, it cannot be displayed in the dedicated monitor mode.

 N1CHCN1
 N1CHCN0
 TV screen mode
 Color format
 normal
 High resolution
 Dedicated monitor
 0
 0
 16 colors
 16 colors
 16 colors
 Palette format
 0
 1
 256 colors
 256 colors
 256 colors
 Palette format
 1
 0
 2048 colors
 2048 colors
 2048 colors
 Palette format
 1
 1
 32768 colors
 32768 colors
 32768 colors
 RGB format
[Note] When used for EXBG, when the set values are N1CHCN1 = 1 and N1CHCN0 = 1, the colors will be 16.77 million.

 NnCHCN0
 TV screen mode
 Color format
 normal
 High resolution
 Dedicated monitor
 0
 16 colors
 16 colors
 16 colors
 Palette format
 1
 256 colors
 256 colors
 256 colors
 Palette format
Note The bit name n can be 2 or 3.

 R0CHCN2
 R0CHCN1
 R0CHCN0
 TV screen mode
 Color format
 normal
 High resolution
 Dedicated monitor
 0
 0
 0
 16 colors
 16 colors
 Cannot be displayed
 Palette format
 0
 0
 1
 256 colors
 256 colors
 Cannot be displayed
 Palette format
 0
 1
 0
 2048 colors
 2048 colors
 Cannot be displayed
 Palette format
 0
 1
 1
 32768 colors
 32768 colors
 Cannot be displayed
 RGB format
 1
 0
 0
 16.77 million colors
 Setting prohibited
 Cannot be displayed
 RGB format
 1
 0
 1
 Setting prohibited (do not set)
 1
 1
 0
 Setting prohibited (do not set)
 1
 1
 1
 Setting prohibited (do not set)

Depending on the number of colors of NBG0 and NBG1, a scroll screen that cannot be displayed may appear. If NBG0 is set to 2048 or 32768 colors, NBG2 cannot be displayed.
If NBG0 is set to 16.77 million colors, NBG1 to NBG3 cannot be displayed.
If NBG1 is set to 2048 colors or 32768 colors, NBG3 cannot be displayed.

　　　　　

Bit map size bit : Bit map size bit (N0BMSZ1, N0BMSZ0, N1BMSZ1, N1BMSZ0, R0BMSZ)
Specify the bitmap size of each screen when displaying in bitmap format.

 N0BMSZ1, N0BMSZ0
 180028H
 Bits 3, 2
 For NBG0
 N1BMSZ1, N1BMSZ0
 180028H
 Bits 11, 10
 For NBG1
 R0BMSZ
 18002AH
 Bit 10
 For RBG0

 NnBMSZ1
 NnBMSZ0
 Bitmap size
 0
 0
 512 dots wide x 256 dots high
 0
 1
 512 dots wide x 512 dots high
 1
 0
 1024 dots wide x 256 dots high
 1
 1
 1024 dots wide x 512 dots high
Note The bit name n can be 0 or 1.

 R0BMSZ
 Bitmap size
 0
 512 dots wide x 256 dots high
 1
 512 dots wide x 512 dots high

　　　　　

Bit map enable bit : Bit map enable bit (N0BMEN, N1BMEN, R0BMEN)
Specifies whether to display the scroll screen in bitmap format.

 N0BMEN
 180028H
 Bit 1
 For NBG0
 N1BMEN
 180028H
 Bit 9
 For NBG1
 R0BMEN
 18002AH
 Bit 9
 For RBG0

 xxBMEN
 Screen display format
 0
 Cell format
 1
 Bitmap format
Note The bit name xx can be N0, N1, or R0.

　　　　　

Character size bit : Character size bit (N0CHSZ, N1CHSZ, N2CHSZ, N3CHSZ, R0CHSZ)
Specify the character size when displaying the scroll screen in cell format.

 N0CHSZ
 180028H
 Bit 0
 For NBG0 (or for RBG1)
 N1CHSZ
 180028H
 Bit 8
 For NBG1
 N2CHSZ
 18002AH
 Bit 0
 For NBG2
 N3CHSZ
 18002AH
 Bit 4
 For NBG3
 R0CHSZ
 18002AH
 Bit 8
 For RBG0

 xxCHSZ
 Character pattern size
 0
 1 horizontal cell x 1 vertical cell
 1
 2 horizontal cells x 2 vertical cells
Note The bit name xx can be N0, N1, N2, N3, or R0.

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