108 Chapter 4
82h Detect and install external RS232 ports
83h Configure non-MCD IDE controllers
84h Detect and install external parallel ports
85h Initialize PC-compatible PnP ISA devices
86h Re-initialize onboard I/O ports
87h Configure Motherboard Configurable
Devices (optional)
88h Initialize BIOS Area
89h Enable Non-Maskable Interrupts (NMIs)
8Ah Initialize Extended BIOS Data Area
8Bh Test and initialize PS/2 mouse
8Ch Initialize floppy controller
8Fh Determine number of ATA drives
(optional)
90h Initialize hard-disk controllers
91h Initialize local-bus hard-disk controllers
92h Jump to UserPatch2
93h Build MPTABLE for multi-processor
boards
95h Install CD ROM for boot
96h Clear huge ES segment register
97h Fixup Multi Processor table
98h 1-2 Search for option ROMs. One long, two
short beeps on checksum failure.
99h Check for SMART drive (optional)
9Ah Shadow option ROMs
9Ch Set up Power Management
9Dh Initialize security engine (optional)
9Eh Enable hardware interrupts
9Fh Determine number of ATA and SCSI
drives
A0h Set time of day
A2h Check key lock
A4h Initialize Typematic rate
A8h Erase F2 prompt
AAh Scan for F2 key stroke
ACh Enter SETUP
AEh Clear Boot flag
B0h Check for errors
B2h POST done- prepare to boot operating
system
B4h 1 One short beep before boot
B5h Terminate QuietBoot (optional)
B6h Check password (optional)
Code Beeps POST Routine Description