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★ HARDWARE Manual ★ VDP2 User's Manual ★ Chapter 4 Scroll screen
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●Pattern name data

Pattern name data consists of the following four data, totaling 26 bits.

The size of pattern name data on the pattern name table can be selected from 1 word or 2 words. In the case of one word, it is not possible to specify all the necessary pattern name data, so it is supplemented with auxiliary data in the lower 10 bits of the pattern name control register. The structure of pattern name data changes depending on the character size, number of character colors, and character number assistance mode. Character number auxiliary mode specifies the number of character number bits and whether the character can use the inversion function when the pattern name data size on the pattern name table is 1 word. Character number assistance modes are shown in Table 4.5. The structure of 2-word pattern name data is shown in Figure 4.9, and the structure of 1-word pattern name data is shown in Table 4.6 and Figure 4.10.

Table 4.5 Character number assistance mode
 character number
 Auxiliary mode
 process
 0
 The character number that can be specified for pattern name data is 10 bits.
 Reverse function can be specified for each character
 1
 The character number that can be specified for pattern name data is 12 bits.
 Reverse function not available

Figure 4.9 Bit configuration when pattern name data is 2 words
 bit31
 bit30
 bit29
 bit28
 bit27
 bit26
 bit25
 bit24
 bit23
 bit22
 bit21
 bit20
 bit19
 bit18
 bit17
 bit16
Reversing function special features - pallet number
top and bottom left and right PR CC - 6 5 4 3 2 1 0

 bit15
 bit14
 bit13
 bit12
 bit11
 bit10
 bit9
 bit8
 bit7
 bit6
 bit5
 bit4
 bit3
 bit2
 bit1
 bit0
- character number
- 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

Table 4.6 Bit configuration when pattern name data is 1 word
 charactor
 size
 charactor
 Number of colors
 Auxiliary mode
 charactor
 number
 pallet
 number
 special features
 Reversing function
(1)
 1×1
 16
 0
 15 *1
 7
 2
 2
(2)
 1×1
 16
 1
 15 *2
 7
 2
 −
(3)
 1×1
 Other than 16
 0
 15 *1
 3
 2
 2
(4)
 1×1
 Other than 16
 1
 15 *2
 3
 2
 −
(5)
 2×2
 16
 0
 15 *3
 7
 2
 2
(6)
 2×2
 16
 1
 15 *4
 7
 2
 −
(7)
 2×2
 Other than 16
 0
 15 *3
 3
 2
 2
(8)
 2×2
 Other than 16
 1
 15 *4
 3
 2
 −
(9)
 2 words
 15
 7
 2
 2
[note]
*1 Specify bits 9 to 0 in the pattern name data.
*2 Specify bits 11 to 0 in the pattern name data.
*3 Specify bits 11 to 2 in the pattern name data.
*4 Specify bits 13 to 2 in the pattern name data.

Figure 4.10 Bit configuration when pattern name data is 1 word

(1) Character size: 1 cell horizontally x 1 cell vertically Number of character colors: 16 colors Character number auxiliary mode: Mode 0

●Pattern name data in the pattern name table
 bit15
 bit14
 bit13
 bit12
 bit11
 bit10
 bit9
 bit8
 bit7
 bit6
 bit5
 bit4
 bit3
 bit2
 bit1
 bit0
pallet number Reversing function character number
3 2 1 0 top and bottom left and right 9 8 7 6 5 4 3 2 1 0

●Auxiliary data in pattern name control register
 bit9
 bit8
 bit7
 bit6
 bit5
 bit4
 bit3
 bit2
 bit1
 bit0
special features pallet number character number
PR CC 6 5 4 14 13 12 11 10
PR: Special priority bit
CC: Special color operation bit 


(2) Character size: 1 cell horizontally x 1 cell vertically Number of character colors: 16 colors Character number auxiliary mode: Mode 1

●Pattern name data in the pattern name table
 bit15
 bit14
 bit13
 bit12
 bit11
 bit10
 bit9
 bit8
 bit7
 bit6
 bit5
 bit4
 bit3
 bit2
 bit1
 bit0
pallet number character number
3 2 1 0 11 10 9 8 7 6 5 4 3 2 1 0

●Auxiliary data in pattern name control register
 bit9
 bit8
 bit7
 bit6
 bit5
 bit4
 bit3
 bit2
 bit1
 bit0
special features pallet number character number
PR CC 6 5 4 14 13 12 - -
PR: Special priority bit
CC: Special color operation bit
[Note] "-" is ignored


(3) Character size: 1 cell horizontally x 1 cell vertically Number of character colors: Other than 16 colors Character number auxiliary mode: Mode 0

●Pattern name data in the pattern name table
 bit15
 bit14
 bit13
 bit12
 bit11
 bit10
 bit9
 bit8
 bit7
 bit6
 bit5
 bit4
 bit3
 bit2
 bit1
 bit0
pallet number Reversing function character number
- 6 5 4 top and bottom left and right 9 8 7 6 5 4 3 2 1 0
[Note] "-" is ignored

●Auxiliary data in pattern name control register
 bit9
 bit8
 bit7
 bit6
 bit5
 bit4
 bit3
 bit2
 bit1
 bit0
special features pallet number character number
PR CC - - - 14 13 12 11 10
PR: Special priority bit
CC: Special color operation bit
[Note] "-" is ignored


(4) Character size: 1 cell horizontally x 1 cell vertically Number of character colors: Other than 16 colors Character number auxiliary mode: Mode 1

●Pattern name data in the pattern name table
 bit15
 bit14
 bit13
 bit12
 bit11
 bit10
 bit9
 bit8
 bit7
 bit6
 bit5
 bit4
 bit3
 bit2
 bit1
 bit0
pallet number character number
- 6 5 4 11 10 9 8 7 6 5 4 3 2 1 0

●Auxiliary data in pattern name control register
 bit9
 bit8
 bit7
 bit6
 bit5
 bit4
 bit3
 bit2
 bit1
 bit0
special features pallet number character number
PR CC - - - 14 13 12 - -
PR: Special priority bit
CC: Special color operation bit
[Note] "-" is ignored


(5) Character size: 2 cells horizontally x 2 cells vertically Number of character colors: 16 colors Character number auxiliary mode: Mode 0

●Pattern name data in the pattern name table
 bit15
 bit14
 bit13
 bit12
 bit11
 bit10
 bit9
 bit8
 bit7
 bit6
 bit5
 bit4
 bit3
 bit2
 bit1
 bit0
pallet number Reversing function character number
3 2 1 0 top and bottom left and right 11 10 9 8 7 6 5 4 3 2

●Auxiliary data in pattern name control register
 bit9
 bit8
 bit7
 bit6
 bit5
 bit4
 bit3
 bit2
 bit1
 bit0
special features pallet number character number
PR CC 6 5 4 14 13 12 1 0
PR: Special priority bit
CC: Special color operation bit 


(6) Character size: 2 cells horizontally x 2 cells vertically Number of character colors: Other than 16 colors Character number auxiliary mode: Mode 1

●Pattern name data in the pattern name table
 bit15
 bit14
 bit13
 bit12
 bit11
 bit10
 bit9
 bit8
 bit7
 bit6
 bit5
 bit4
 bit3
 bit2
 bit1
 bit0
pallet number character number
- 6 5 4 13 12 11 10 9 8 7 6 5 4 3 2

●Auxiliary data in pattern name control register
 bit9
 bit8
 bit7
 bit6
 bit5
 bit4
 bit3
 bit2
 bit1
 bit0
special features pallet number character number
PR CC 6 5 4 14 - - 1 0
PR: Special priority bit
CC: Special color operation bit
[Note] "-" is ignored

◆Character number
The character number is 15-bit data that specifies the start address of the character pattern to be displayed at that position. The boundary of the character pattern based on this character number is always 20H. Note that if the VRAM capacity is 4M bits, the most significant bit (bit 14) of the character number is not used.

◆Palette number
The palette number is 7-bit data that specifies the starting address of the color palette used for the character pattern displayed at that position. This data is only used when the color format is palette format, not when the color format is RGB format. The palette number is attached to the dot color code of the character pattern, making it 11 bits of dot color data, so the bits used will change depending on the number of character colors. Figure 4.11 shows the structure of 11-bit dot color data.

Figure 4.11 Dot color data based on character color number
●Number of character colors: 16 colors
 bit10
 bit9
 bit8
 bit7
 bit6
 bit5
 bit4
 bit3
 bit2
 bit1
 bit0
pallet number dot color code
6 5 4 3 2 1 0 3 2 1 0
●Number of character colors: 256 colors
 bit10
 bit9
 bit8
 bit7
 bit6
 bit5
 bit4
 bit3
 bit2
 bit1
 bit0
pallet number dot color code
6 5 4 7 6 5 4 3 2 1 0
●Number of character colors: 2048 colors
 bit10
 bit9
 bit8
 bit7
 bit6
 bit5
 bit4
 bit3
 bit2
 bit1
 bit0
dot color code
10 9 8 7 6 5 4 3 2 1 0

◆Special function bit
The special function bit is 2-bit data that specifies whether to use a special function for the character pattern displayed at that position. The special function bits include a special priority bit that controls the priority number and a special color calculation bit that controls color calculation. For details on special priority bits, see " 11.2 Special Priority Function ." For details on special color calculation bits, please refer to " 12.2 Special color calculation function ".

◆Reverse function bit
The reverse function bit is 2-bit data that specifies whether to use the reverse function for the character pattern displayed at that position. The flip function bits include the vertical flip 064 horizontal flip bit, which flips the character pattern vertically. Table 4.7 shows the inversion function bits, and Figure 4.12 shows an example of character pattern inversion display.

Table 4.7 Invert function bit
 Vertical flip bit
 Left/right flip bit
 process
0 0
 Does not flip either vertically or horizontally
0 1
 Flip left and right only
1 0
 Flip only the top and bottom
1 1
 Flip both vertically and horizontally

Figure 4.12 Reverse display of character pattern

◆Limitations on the horizontal flip function bit
The cell format normal scroll screen (NBG0,1) horizontal inversion function bit is valid only when the number of character colors is 16 or 256 colors. Otherwise, do not set it to "1".

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