<30/86> VDP2 User's Manual / 4.8 Map-3

★ 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 write-only 16-bit register located at addresses 18003CH to 18003EH. After turning on the power or resetting, the value will be cleared to 0, so be sure to set it.

MPOFN 18003CH

---	N3MP8	N3MP7	N3MP6	---	N2MP8	N2MP7	N2MP6
15	14	13	12	11	Ten	09 09	08 08

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

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

MPOFR 18003EH

---	N3MP8	N3MP7	N3MP6	---	N2MP8	N2MP7	N2MP6
15	14	13	12	11	Ten	09 09	08 08

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

Map offset bit : Map offset bit

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

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

N0MP8 to 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 boundary address of the bitmap pattern is as follows.

xxMP8	xxMP7	xxMP6	Boundary address value of bitmap pattern
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