03 |
ROM BIOS checksum failure |
04 |
DMA page register failure |
05 |
Keyboard controller selftest
failure |
08 |
Memory refresh circuitry
failure |
09 |
Master 16-bit DMA controller
failure |
09 |
Slave 8-bit DMA controller
failure |
0A |
Base 64K pattern test
failure |
0A |
Base 64K parity circuitry
failure |
0A |
Base 64K parity error |
0A |
Base 64K data bus failure |
0A |
Base 64K address bus
failure |
0A |
Base 64K block access
read failure |
0A |
Base 64K block access
write failure |
0B |
Master 8259 failure |
0B |
Slave 8259 failure |
0C |
Master 8259 interrupt
address failure |
0C |
Slave 8259 interrupt
address failure |
0C |
8259 interrupt address
error |
0C |
Master 8259 stuck interrupt
error |
0C |
Slave 8259 stuck interrupt
error |
0C |
System timer 8254 channel
0/IRQ 0 failure |
0D |
8254 channel 0, speaker
detect, failure |
0E |
8254 channel 2 speaker
failure |
0E |
8254 OUT2, speaker detect,
failure |
0F |
CMOS RAM read/write test
failure |
0F |
CMOS read/write test
failure |
0F |
RTC periodic interrupt
/ IRQ 8 failure |
10 |
Video ROM checksum failure |
11 |
RTC battery discharged
or CMOS contents corrupt |
12 |
Keyboard controller failure |
12 |
Keyboard error, stuck
key |
14 |
Memory parity error |
14 |
I/O channel error |
14 |
RAM pattern test failed |
15 |
Keyboard failure or no
keyboard present |
17 |
A20 test failure caused
by 8042 timeout |
17 |
A20 gate stuck in disabled
state |
17 |
A20 gate stuck in asserted
state |
18 |
Parity circuit failure |
19 |
Data bus test failure,
address line test failed, block access read failure, block access
read/write failure, or banks decode to same location |
1A |
Real time clock is not
updating |
1A |
Real time clock settings
are invalid |
1E |
Diskette CMOS configuration
invalid, diskette controller failure, or diskette drive A: failure
or diskette drive B: failure |
1F |
FDD CMOS configuration
invalid, fixed disk C: failure, or fixed disk D: failure |
20 |
Fixed disk configuration
change, diskette configuration change, serial port configuration
change, parallel port configuration change, video configuration
change, memory configuration change, or coprocessor configuration
change |
21 |
System key is in locked
position |
29 |
Adapter ROM checksum
failure |
00 |
Cold start |
01 |
Initialize
KBD controller, Disable CPU cache, Initialize onboard I/O chipset,
Test RAM size |
02 |
Disable critical
I/O |
03 |
Checksum
the BIOS ROM |
04 |
Test page
register |
05 |
Enable A20
gate, issue 8042 keyboard controller self test |
06 |
Initialize
ISA I/O |
07 |
Warm initialize
KBD controller & I/O chipset |
08 |
Refresh toggle
test |
09 |
Test DMA
master & slave registers |
0A |
Test first
64KB of base memory |
0B |
Test master
8259 mask, test slave 8259 mask |
0C |
Test 8259
slave, initialize interrupt vectors 00-77h, initialize keyboard
buffer variables |
0D |
Test timer
0, 8254 channel 0 |
0E |
Test 8254
channel 2, speaker channel |
10 |
Turn on monitor,
show error messages |
11 |
Read and
checksum the CMOS |
12 |
Call video
ROM initialization routines |
13 |
Set 8Mhz
AT-bus |
14 |
Size and
test memory, stuck NMI check |
15 |
No keyboard
and power on, retry keyboard initialization |
16 |
Size and
test CPU cache |
17 |
Test A20
off and on gates |
18 |
External
memory size, stuck NMI check |
19 |
System memory
size, stuck NMI check |
1A |
Test RTC
time |
1B |
Determine
serial ports |
1C |
Determine
parallel ports |
1D |
Initialize
numeric coprocessor |
1E |
Determine
floppy diskette drive controllers |
1F |
Determine
IDE controllers |
20 |
Display CMOS
configuration changes |
21 |
Clear screens |
22 |
Set/reset
numlock LED, security functions |
23 |
Final onboard
serial and parallel ports check |
24 |
Set keyboard
typematic rate |
25 |
Initialize
floppy controller |
26 |
Initialize
ATA discs |
27 |
Set video
mode for primary adapter` |
28 |
Cyrix WB-CPU
support, purge 8259 slave |
29 |
Reset A20
to OFF, Install adapter ROM's |
2A |
Clear primary
screen, convert RTC to system ticks, set final DOS timer variable |
2B |
Enable NMI
and latch |
2E |
Fast A20,
fix A20 |
2F |
Purge 8259
slave, control to interrupt 19 boot |
32 |
Test CPU
burst |
34 |
Determine
8042, set warm boot flag STS 2 |
35 |
Test high
memory area wrap, verify A20 via F000:10 high memory area |
37 |
CPU step
NZ, CPUID, disable CPU features |
38 |
Set 8042
pins |
39 |
PCI bus |
3A |
Scan PCI
bus |
3B |
Initialize
PCI bus with intermediate defaults |
3C |
Initialize
PCI OEM: OEM bridge |
3D |
PCI bus and
Plug & Play: initialize AT slotman from AT bus CDE usage |
3E |
Find phantom
CDE ROM PCI cards |
3F |
PCI bus:
final fast back-to-back state |
40 |
OEM post
initialization, hook audio |
41 |
Allocate
I/O on PCI bus, logs in PCI-IDE |
42 |
Hook PCI-ATA
chips |
43 |
Allocate
IRQ's to PCI bus, enable ATA IRQ's |
44 |
Allocate
and enable PCI memory/ROM space |
45 |
Determine
PS/2 mouse |
46 |
Map IRQ's
to PCI bus, enable ATA IRQ's |
47 |
PCI-ROM install,
note user CMOS |
48 |
If setup
conditions: execute setup utility |
49 |
Test F000,
transfer EPROM to shadow RAM |
4A |
Hook VLATA
chip |
4B |
Identify
and spin up all drives |
4C |
Detect secondary
IRQ, if VL/AT bus IDE exists but it's IRQ not known yet |
4D |
Detect /log
32-bit I/O ATA devices |
4E |
Atapi drive
M/S bitmap to shadow RAM, set interrupt 13 vector |
4F |
Finalize
shadow RAM |
50 |
Chain interrupt
13 |
51 |
Load Plug
& Play, processor vector initialized, BIOS vector initialized,
OEM vector initialized |
52 |
Scan for
Plug & Play, update Plug & Play device count |
53 |
Supplement
IRQ usage, AT IRQ's |
54 |
Conditionally
assign everything Plug & Play wants |
58 |
OEM custom
boot sequence just prior to interrupt 19 boot |
59 |
Pass control
to interrupt 19 boot |
5A |
Display MR
BIOS logo |
88 |
Dead motherboard
and/or BIOS ROM |
FF |
BIOS POST
finished |