M69000 Asiliant Technologies, M69000 Datasheet - Page 134

• Manufacturer Part Number: M69000
• Manufacturer: Asiliant Technologies

Specifications of M69000

• Lead Free Status / Rohs Status: Supplier Unconfirmed

CR78
read/write at I/O address 3B5h/3D5h with index at address 3B4h/3D4h set to 78h
7
6-5
4-0
&+,36
Redux En
Vertical
(0)
7
Vertical Reduction Enable
0: Vertcal reduction is disabled. This is the default after reset.
Reserved
These bits always return the value of 0 when read.
Vertical Reduction Line Dropping Interval
69000 Databook
NTSC/PAL Vertical Reduction Register
Reserved
1: Vertical reduction is enabled
When bit 7 of this register is set to 1, these 5 bits specify the number of scanlines remaining
(those which will be drawn on the display) between each of the scanlines that are to be
dropped (those which will NOT be drawn on the display).
(0)
6
Reserved
4 3 2 1 0
0 0 0 0 0
0 0 0 0 1
0 0 0 1 0
1 1 1 1 1
(0)
5
Bit
to
Subject to Change Without Notice
CRT Controller Registers
Number of Scanlines Remaining
Between Dropped Scanlines
4
Reserved
Reserved
Vertical Reduction Line Dropping Interval
31
to
2
3
(0:0000)
2
Revision 1.3 8/31/98
1
0
9-41