M69000 Asiliant Technologies, M69000 Datasheet - Page 89

• Manufacturer Part Number: M69000
• Manufacturer: Asiliant Technologies

Specifications of M69000

• Lead Free Status / Rohs Status: Supplier Unconfirmed

ST01
read-only at I/O Address 3BAh/3DAh
7
Note: This bit is largely unused by current software.
6
5-4
3
2-1
0
&+,36
VSYNC
Output
7
VSYNC Output
0: The VSYNC output pin is currently inactive.
1: The VSYNC output pin is currently active.
Reserved
This bit returns the value of 0 when read.
Video Feedback 1, 0
These are diagnostic video bits that are programmably connected to two of the eight color bits sent
to the palette. Bits 4 and 5 of the Color Plane Enable Register (AR12) select which two of the eight
possible color bits become connected to these 2 bits of this register. The current software normally
does not use these 2 bits. They exist for EGA compatibility.
Vertical Retrace
0: Indicates that a vertical retrace interval is not taking place.
1: Indicates that a vertical retrace interval is taking place.
Reserved
These bits return the value of 0 when read.
Display Enable
0: Data for the active display area is being drawn to the display. Neither a horizontal retrace interval
nor a vertical retrace interval is currently taking place.
1: Either a horizontal or vertical retrace interval is currently taking place.
69000 Databook
Input Status Register 1
Reserved
6
Video Feedback 1,0
5
General Control and Status Registers
Subject to Change Without Notice
4
Retrace
Vertical
3
2
Reserved
Revision 1.3 8/31/98
1
Display
Enable
0
8-3