Code |
Beeps |
POST Routine Description |
02h |
|
Verify Real
Mode |
03h |
|
Disable
Non-Maskable Interrupt (NM) |
04h |
|
Get CPU type |
06h |
|
Initialize
system hardware |
08h |
|
Initialize
chipset with Initial POST values |
09h |
|
Set IN POST
flag |
0Ah |
|
Initialize CPU
registers |
0Bh |
|
Enable CPU
cache |
0Ch |
|
Initialize
caches to initial POST values |
0Eh |
|
Initialize I/O
component |
0Fh |
|
Initialize the
local bus IDE |
10h |
|
Initialize
Power Management |
11h |
|
Load alternate
registers with initial POST values |
12h |
|
Restore CPU
control word during warm boost |
13h |
|
Initialize PCI
Bus Mastering devices |
14h |
|
Initialize
keyboard controller |
16h |
1-2-2-3 |
BIOS ROM
Checksum |
17h |
|
Initialize
cache before memory autosize |
18h |
|
8254 timer
initialization |
1Ah |
|
8237 DMA
controller initialization |
1Ch |
|
Reset
Programmable Interrupt Controller |
20h |
1-3-1-1 |
Test DRAM
refresh |
22h |
1-3-1-3 |
Test 8742
Keyboard Controller |
24h |
|
Set ES segment
register to 4 GB |
26h |
|
Enable A20 line |
28h |
|
Autosize DRAM |
29h |
|
Initialize POST
Memory Manager |
2Ah |
|
Clear 512 KB
base RAM |
2Ch |
1-3-4-2 |
RAM failure on
address line xxxx* |
2Eh |
1-3-4-3 |
RAM failure on
data bits xxxx* of low byte of memory bus |
2Fh |
|
Enable cache
before system BIOS shadow |
30th |
1-4-1-1 |
RAM failure on
data bits xxxx*of high byte memory bus |
32h |
|
Test CPU
bus-clock frequency |
33h |
|
Initialize
Phoenix Dispatch Manager |
36h |
|
Warm start shut
down |
38h |
|
Shadow system
BIOS ROM |
3Ah |
|
Autosize cache |
3Ch |
|
Advanced
configuration of chipset registers |
3Dh |
|
Load alternate
registers with CMOS values |
42h |
|
Initialize
interrupt vectors |
45h |
|
POST device
initialization |
46h |
2-1-2-3 |
Check ROM
copyright notice |
48h |
|
Check Video
configuration against CMOS |
49h |
|
Initialize PCI
bus and devices |
4Ah |
|
Initialize all
video adapters in system |
4Bh |
|
QuietBoot start
(optional) |
4Ch |
|
Shadow video
BIOS ROM |
4Eh |
|
Display BIOS
copyright notice |
50Eh |
|
Display CPU
type and speed |
51h |
|
Initialize EISA
board |
52h |
|
Test keyboard |
54h |
|
Set key click
if enabled |
58h |
2-2-3-1 |
Test for
unexpected interrupts |
59h |
|
Initialize POST
display service |
5Ah |
|
Display prompt
"Press F2 to enter SetUP" |
5Bh |
|
Disable CPU
cache |
5Ch |
|
Test RAM
between 512 and 640 KB |
60h |
|
Test extended
memory |
62h |
|
Test extended
memory address lines |
64h |
|
Jump to
UserPatchI |
66h |
|
Configure
advanced cache registers |
67h |
|
Initialize
Multi Processor APIC |
68h |
|
Enable external
and CPU cache |
69h |
|
Setup System
Management Mode (SMM) area |
6Ah |
|
Display
external L2 cache size |
6Bh |
|
Load custom
defaults (optional) |
6Ch |
|
Display
shadow-area message |
6Eh |
|
Display
possible high address for UMB recovery |
70h |
|
Display error
messages |
72h |
|
Check for
configuration errors |
76h |
|
Check for
keyboard errors |
7Ch |
|
Set up hardware
interrupt vectors |
7Eh |
|
Initialize
coprocessor if present |
80h |
|
Disable onboard
Super I/O ports and IRQs |
81h |
|
Late POST
device initialization |
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 |
|
Reinitialize
onboard I/O ports |
87h |
|
Configure
Motherboard Configurable Devices (optional) |
88h |
|
Initialize BIOS
Data Area |
89h |
|
Enable
Non-Maskable Interrupts (NMIs) |
8Ah |
|
Initialize
Extended BIOS Data Area |
8Bh |
|
Test and
initialize PS/2 mouse |
8Ch |
|
Initialize
floppy controller |
81h |
|
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 shot beep
before boot |
B5h |
|
Terminate
QuietBoot (optional) |
B6h |
|
Check password
(optional) |
B9h |
|
Prepare Boot |
BAh |
|
Initialize DMI
Parameters |
BBh |
|
Initialize PnP
Option ROMs |
BCh |
|
Clear parity
checkers |
BDh |
|
Display
MultiBoot menu |
BEh |
|
Clear screen
(optional) |
BFh |
|
check virus and
back up reminders |
C0h |
|
Try to boot
with INT 19 |
C1h |
|
Initialize POST
Error Manager (PEM) |
C2h |
|
Initialize
error logging |
C3h |
|
Initialize
error display function |
C4h |
|
Initialize
system error handler |
C5h |
|
PnPnd dual CMOS
(optional) |
C6h |
|
Initialize
notebook docking (optional) |
C7h |
|
Initialize
notebook docking late |
C8h |
|
Force check
(optional) |
C9h |
|
Extended
checksum (optional) |
D2h |
|
Unknown
interrupts |