IBM Personal System/2 65 SX User Manual

System-Board Enable/Setup Register (Hex 0094)
This is a read/write register. All bits in this register default to 1
(enabled).
Bit Function
7 Enable/-Setup System-Board Functions
6 Reserved
5 Enable/-Setup Video Subsystem
4-0 Reserved
Figure 2-3. System-Board Enable/Setup Register (Hex 0094)
Bit7 When set to 0, this bit places various system-board I/O
functions in the setup mode. The diskette-drive controller,
serial port, and parallel port are controlled through
System-Board POS Register 2 (hex 0102). The POS
information for memory is in System-Board POS Register
3 (hex 0103), POS Register 4 (hex 0104), and POS Register
5 (hex 0105).
When set to 1, this bit enables the system-board functions.
Bité6 This bit is reserved.
Bit 5 When set to 0, this bit places the video subsystem in the
setup mode, and control is through POS Register 2 (hex
0102). When this bit is set to 1 and bit 0 in POS Register 2
is set to 1, video is enabled.
Bit 0 of POS Register 2 is the video-enabie bit. When this
bit is set to 0, the video subsystem does not respond to
commands, addresses, or data. If video is being
generated when the video-enable bit is set to 0, the output
is still generated. For information on BIOS calls to enable
or disable the video, see the /BM Personal System/2 and
Personal Computer BIOS Interface Technical Reference
manual.
Note: When video is disabled, access to the
digital-to-analog converter (DAC) registers is
disabled.
Bits 4-0 These bits are reserved.
Model 65 POS — October 1990 2-7

IBM Personal System/2 65 SX Specifications

General

Brand	IBM
Model	Personal System/2 65 SX
Category	Desktop
Language	English