© 1985 ASCII CORP. / NIPPON GAKKI CO.
Page 43 of 108
© 2010-2015 Eugeny Brychkov
3.5.1. Screen map and pattern tables
Unlike in other modes, in this mode screen is divided vertically into three logical parts.
Every part has its own pattern generator and pattern color tables, but all of them share the
same pattern layout table, one after another. Screen map is provided below.
Columns
0
1
2
3
31
←
X
0
0, 0
1, 0
2, 0
3, 0
…
…
31, 0
1
0, 1
1, 1
2, 1
3, 1
…
…
31, 1
…
…
… … … … …
… … … … … … …
0, 7
1, 7
2, 7
…
…
…
31, 7
Upper
⅓
of
the screen
0, 8
1, 8
2, 8
…
…
…
31, 8
… … … … … … …
… … … … … … …
… … … … … … …
0, 15
1, 15
2, 15
…
…
…
31, 15
Middle
⅓
of
the screen
0, 16
1, 16
2, 16
…
…
…
31, 16
… … … … … … …
… …
…
… … … …
22
0, 22
1, 22
2, 22
…
…
…
31, 22
23
0, 23
1, 23
2, 23
…
…
…
31, 23
Lower
⅓
of
the screen
Rows
↑
Y
Pattern generator table
Pattern color table
(base address) 00000h
007FFh
Pattern images for upper
⅓
of the screen
(256)
Pattern colors for upper
⅓
of the screen (256)
00800h
00FFFh
Pattern images for middle
⅓
of the screen
(256)
Pattern colors for middle
⅓
of the screen (256)
01000h
017FFh
Pattern images for lower
⅓
of the screen
(256)
Pattern colors for lower
⅓
of the screen (256)