VGA Register Programming (38715)

The information in this article applies to:
    Microsoft Mouse driver for MS-DOS 6.x
    Microsoft Mouse driver for MS-DOS 7.x
    Microsoft Mouse driver for MS-DOS 8.x
    Microsoft Mouse driver for MS-DOS 9.0

This article was previously published under Q38715


The EGA register interface also needs to be used for VGA programming. When programming the VGA in EGA modes, using the interface is identical to using it with the EGA. However, the VGA makes use of an extra Attribute Controller register, 14h, Color Select. Where the EGA has 20 Attribute Controller registers (0 through 13h), the VGA has 21 (0 through 14h).

Using function F7 of the EGA interface needs special attention. When setting the Attribute Controller chip, all registers for the chip need to be set any time the chip is accessed. If a register is not defined, the register interface uses whatever random value is in that location.

Modification Type: Major Last Reviewed: 9/23/2003
Keywords: KB38715