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

●Map offset register

The map offset register specifies the map offset value. This is a 16-bit write-only register located at addresses 18003CH to 18003EH. The value is cleared to 0 after power-on or reset, so be sure to set it.

MPOFN 18003CH
   15   
   14   
   13   
   12   
   11   
   10   
   09   
   08   
 -
 N3MP8
 N3MP7
 N3MP6
 -
 N2MP8
 N2MP7
 N2MP6

   07   
   06   
   05   
   04   
   03   
   02   
   01   
   00   
 -
 N1MP8
 N1MP7
 N1MP6
 -
 N0MP8
 N0MP7
 N0MP6

MPOFR 18003EH
   15   
   14   
   13   
   12   
   11   
   10   
   09   
   08   
 -
 N3MP8
 N3MP7
 N3MP6
 -
 N2MP8
 N2MP7
 N2MP6

   07   
   06   
   05   
   04   
   03   
   02   
   01   
   00   
 -
 -
 -
 -
 -
 RAMP8
 RAMP7
 RAMP6

　　　　　　
Map offset bit : Map offset bit
(N0MP8~N0MP6, N1MP8~N1MP6, N2MP8~N2MP6, N3MP8~N3MP6, RAMP8~RAMP6, RBMP8~RBMP6)
If the display format of the scroll screen is cell format, specify the 3-bit map offset value to be added to the upper part of the 6-bit map register. For bitmap formats, specify the boundaries of the bitmap pattern.

N0MP8～N0MP6 18003CH bits 2-0 For NBG0
N1MP8～N1MP6 18003CH bits 6-4 For NBG1
N2MP8～N2MP6 18003CH bits 10-8 For NBG2
N3MP8～N3MP6 18003CH bits 14-12 For NBG3
RAMP8～RAMP6 18003EH bits 2-0 For rotation parameter A
RBMP8~RBMP6 18003EH bits 6-4 For rotation parameter B

The address of the bitmap pattern boundary is as follows.
 xxMP8
 xxMP7
 xxMP6
 Bitmap pattern boundary address value
 0
 0
 0
 00000H
 0
 0
 1
 20000H
 0
 1
 0
 40000H
 0
 1
 1
 60000H
 1
 0
 0
 80000H
 1
 0
 1
 A0000H
 1
 1
 0
 C0000H
 1
 1
 1
 E0000H
xx=N0,N1,N2,N3,RA,RB
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★ HARDWARE Manual VDP2 User's Manual ★ Chapter 4 Scroll screen
Copyright SEGA ENTERPRISES, LTD., 1997