Pattern name data

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

Character number 15 bits

Pallet number 7 bits

Special function bit 2 bits

Inversion function bit 2 bits

The character number specifies the start address of the character pattern (VRAM). The palette number specifies the start address of the palette (color RAM) used by the character. The special function bit specifies whether the character uses a special function. The reverse function bit specifies whether to use the vertical flip function or the horizontal flip function.
∙ The size of the pattern name data on the pattern name table can be selected from 1 word or 2 words. In the case of 1 word, it is not possible to specify all necessary pattern name data, so it is supplemented with auxiliary data in the lower 10 bits of the pattern name control register. The pattern name data configuration varies depending on the character size, number of characters, and character number assist 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 1 word, and whether or not the character can use the reverse function. Table 4.5 shows the character number assist mode. 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 assist mode

Character number Auxiliary mode	Processing
0	The character number that can be specified for pattern name data is 10 bits. Invert function can be specified for each character
1	The character number that can be specified for pattern name data is 12 bits. Invert function cannot be used

Figure 4.9 Bit structure when pattern name data is 2 words