<24/86>VDP2 User's Manual/4.6 Pattern Name Table (Page)-1

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■4.6 Pattern name table (page)

A pattern name table (or page) stores pattern name data in VRAM, arranging it in the form of a table that describes how character patterns are laid out in a square with a size of 64 cells horizontally and 64 cells vertically. Pattern name data specifies the start address and other control information of the character pattern stored in VRAM for each character pattern.
The pattern name data on the pattern name table is 1 word or 2 words. If it is 1 word, auxiliary data of the lower 10 bits of the pattern name control register is added to fill in the missing bits.

●Data structure of pattern name table

The VRAM capacity required for a pattern name table of 64 cells horizontally x 64 cells vertically (one page) and the boundary stored in VRAM vary depending on the pattern name data size (number of words) and character size. The capacity of the pattern name table and the data structure of the table are shown in Table 4.4 and "Details".

Table 4.4 Pattern name table capacity and page boundary for one page

pattern name Data size	character size	per page capacity of	When storing in VRAM Poundary	detail
1 word	1 cell horizontal x 1 cell vertical	8192 bytes	2000H	→
1 word	2 cells horizontally x 2 cells vertically	2048 bytes	800H	→
2 words	1 cell horizontal x 1 cell vertical	16384 bytes	4000H	→
2 words	2 cells horizontally x 2 cells vertically	4096 bytes	1000H	→

Reference: For the data structure of the pattern name table, click on the details column of "Table 4.8"

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