Intel 815 Manuel D’Utilisation
Intel® 815 Chipset: Graphics Controller PRM, Rev 1.0
R
80
9.1.1. ST00
Input Status 0
I/O (and Memory Offset) Address: 3C2h
Default: 00h
Attributes: Read
Default: 00h
Attributes: Read
Only
7 6
5 4 3
0
CRT Int
Reserved (00)
RGB Cmp
/ Sen
Reserved (0000)
Bit Descriptions
7
CRT Interrupt Pending. Note that the generation of interrupts can be enabled, through bits [4,5] of the
Vertical Retrace End Register (CR11). This ability to generate interrupts at the start of the vertical
retrace interval is a feature that is typically unused by current software. This bit is here for EGA
compatibility.
Vertical Retrace End Register (CR11). This ability to generate interrupts at the start of the vertical
retrace interval is a feature that is typically unused by current software. This bit is here for EGA
compatibility.
0 = CRT (vertical retrace interval) interrupt is not pending.
1 = CRT (vertical retrace interval) interrupt is pending
6:5
Reserved. Read as 0s.
4
RGB Comparator / Sense. This bit returns the state of the output of the RGB output comparator(s).
BIOS uses this bit to determine whether the display is a color or monochrome CRT.
BIOS uses this bit to determine whether the display is a color or monochrome CRT.
0 = Monochrome
1 = Color
BIOS blanks the screen or clears the frame buffer to display only black. Next, BIOS configures the
D-to-A converters and the comparators to test for the presence of a color display. Finally, if the BIOS
does not detect any colors, it tests for the presence of a display. The result of each such test is read via
this bit.
D-to-A converters and the comparators to test for the presence of a color display. Finally, if the BIOS
does not detect any colors, it tests for the presence of a display. The result of each such test is read via
this bit.
3:0
Reserved. Read as 0s.