<49/86> VDP2 User's Manual / 6.4 Coefficient Table Control-3

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● Coefficient table control register

The coefficient table control register controls the coefficient table. A write-only 16-bit register located at address 1800B4H. After turning on the power or resetting, the value will be cleared to 0, so be sure to set it.

KTCTL 1800B4H

---	---	---	RBKLCE	RBKMD1	RBKMD0	RBKDBS	RBKTE
15	14	13	12	11	Ten	09 09	08 08

07 07
06 06
05 05
04
03 03
02 02
01 01
00
---
---
---
RAKLCE
RAKMD1
RAKMD0
RAKDBS
RAKTE

The coefficient line Color Enable bit: Coefficient line color enable bit (RAKLCE , RBKLCE)

07 07	06 06	05 05	04	03 03	02 02	01 01	00
---	---	---	RAKLCE	RAKMD1	RAKMD0	RAKDBS	RAKTE

Specifies whether to use the line color screen data in the coefficient data.

RAKLCE	1800B4H	Bit 4	For rotation parameter A
RBKLCE	1800B4H	Bit 12	For rotation parameter B

This bit is valid only when the corresponding coefficient table is used and the data size is 2 words.

RxKLCE	process
0	Do not use line color screen data in coefficient data
1	Use the line color screen data in the coefficient data

Note The x in the bit name can be A or B.

Coefficient data mode bit: Coefficient mode bit (RAKMD1, RAKMD0 , RBKMD1, RBKMD0)

Specifies what parameter to use the coefficient data.

RAKMD1, RAKMD0	1800B4H	Bits 3,2	For rotation parameter A
RBKMD1, RBKMD0	1800B4H	Bits 11,10	For rotation parameter B

Pay attention to the timing of rewriting because this bit is always valid.

RxKMD1	RxKMD0	mode	Coefficient data function
0	0	0	Used as scaling factor kx, ky
0	1	1	Used as scaling factor kx
1	0	2	Used as scaling factor ky
1	1	3	Used as viewpoint coordinates Xp after rotation conversion

Note The x in the bit name can be A or B.

Coefficient data size bit: Coefficient data size bit (RAKDBS, RBKDBS)

Specifies the size of the coefficient data.

RAKDBS	1800B4H	Bit 1	For rotation parameter A
RBKDBS	1800B4H	Bit 9	For rotation parameter B

This bit is valid only when the corresponding coefficient table is used.

RxKDBS	Coefficient data size
0	2 words
1	1 word

Note The x in the bit name can be A or B.

Coefficient table enable bit: Coefficient table enable bit (RAKTE, RBKTE)

Specifies whether to use a coefficient table.

RAKTE	1800B4H	Bit 0	For rotation parameter A
RBKTE	1800B4H	Bit 8	For rotation parameter B

RxKTE	process
0	Do not use coefficient table
1	Use a coefficient table

Note The x in the bit name can be A or B.

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★ HARDWARE Manual VDP2 User's Manual ★ Chapter 6 Rotating scroll screen