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

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

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

Table 4.5 Character number auxiliary mode
 Character number auxiliary mode
 process
 0
 The character number that can be specified for the pattern name data is 10 bits.
 Inversion function can be specified for each character
 1
 The character number that can be specified for the pattern name data is 12 bits.
 Invert function cannot be used

Figure 4.9 Bit configuration when the pattern name data is 2 words
 bit31
 bit30
 bit29
 bit28
 bit27
 bit26
 bit25
 bit24
 bit23
 bit22
 bit21
 bit20
 bit19
 bit18
 bit17
 bit16
Inversion function Special features --- Palette number
Up and down 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 Ten 9 8 7 6 5 4 3 2 1 0

Table 4.6 Bit configuration when pattern name data is 1 word
 Character size
 Number of character colors
 Auxiliary mode
 Character number
 Palette
 number
 Special features
 Inversion 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
(Four)
 1 × 1
 Other than 16
 1
 15 * 2
 3
 2
 −
(Five)
 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 for the pattern name data.
* 2 Specify bits 11 to 0 for the pattern name data.
* 3 Specify bits 11 to 2 for the pattern name data.
* 4 Specify bits 13 to 2 for the pattern name data.

Figure 4.10 Bit configuration when the pattern name data is one word

(1) Character size: 1 horizontal cell x 1 vertical cell 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
Palette number Inversion function Character number
3 2 1 0 Up and down Left and right 9 8 7 6 5 4 3 2 1 0

● Auxiliary data in the pattern name control register
 bit9
 bit8
 bit7
 bit6
 bit5
 bit4
 bit3
 bit2
 bit1
 bit0
Special features Palette number Character number
PR CC 6 5 4 14 13 12 11 Ten
PR: Special priority bit
CC: Special color arithmetic bit 


(2) Character size: 1 horizontal cell x 1 vertical cell 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
Palette number Character number
3 2 1 0 11 Ten 9 8 7 6 5 4 3 2 1 0

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


(3) Character size: 1 horizontal cell x 1 vertical cell 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
Palette number Inversion function Character number
--- 6 5 4 Up and down Left and right 9 8 7 6 5 4 3 2 1 0
[Note] "-" is ignored

● Auxiliary data in the pattern name control register
 bit9
 bit8
 bit7
 bit6
 bit5
 bit4
 bit3
 bit2
 bit1
 bit0
Special features Palette number Character number
PR CC --- --- --- 14 13 12 11 Ten
PR: Special priority bit
CC: Special color arithmetic bit
[Note] "-" is ignored


(4) Character size: 1 horizontal cell x 1 vertical cell 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
Palette number Character number
--- 6 5 4 11 Ten 9 8 7 6 5 4 3 2 1 0

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


(5) Character size: 2 horizontal cells x 2 vertical cells 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
Palette number Inversion function Character number
3 2 1 0 Up and down Left and right 11 Ten 9 8 7 6 5 4 3 2

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


(6) Character size: 2 horizontal cells x 2 vertical cells 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
Palette number Character number
--- 6 5 4 13 12 11 Ten 9 8 7 6 5 4 3 2

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

◆ Character number
The character number is 15-bit data and specifies the start address of the character pattern to be displayed at that position. The boundary of the character pattern by this character number is always 20H. 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, and specifies the start address of the color palette used for the character pattern displayed at that position. This data is used only when the color format is palette format, not when it is RGB format. The palette number is attached to the dot color code of the character pattern to make a total of 11 bits of dot color data, so the bits used will change depending on the number of character colors. Figure 4.11 shows the configuration of 11-bit dot color data.

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

◆ Special function bit
The special function bit is 2-bit data and specifies whether to use the 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 operation bit that controls the color operation. For details on the special priority bit, see 11.2 Special Priority Function. For details on the special color calculation bit, refer to " 12.2 Special Color Calculation Function".

◆ Inversion function bit
The inversion function bit is 2-bit data and specifies whether to use the inversion function for the character pattern displayed at that position. The inversion function bits include the upside down 064 left / right inversion bit that inverts the character pattern up / down. Table 4.7 shows the inversion function bits, and Fig. 4.12 shows an example of the inversion display of the character pattern.

Table 4.7 Inversion function bits
 Upside down bit
 Left / right inversion bit
 process
0 0
 Do not flip either up / down or left / right
0 1
 Invert only left and right
1 0
 Invert only upside down
1 1
 Invert both up and down and left and right

Figure 4.12 Reverse display of character patterns

◆ Left / right inversion function Bit limitation
The cell format normal scroll screen (NBG0,1) left / right inversion function bit is valid only when the number of character colors is 16 or 256. Otherwise, do not set it to "1".

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★ HARDWARE Manual VDP2 User's Manual ★ Chapter 4 Scroll screen
Copyright SEGA ENTERPRISES, LTD., 1997