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BIOS PostCodes

Intel Motherboards:

Intel NA440BX/N440BX BIOS Post Codes:

Standard BIOS Port 80 Codes in Execution Sequence During POST

02 Verify real mode
12 Restore processor control word during warm boot (only occurs on warm boot)
24 Set ES segment register to 4GB
04 Get processor type
06 Initialize system hardware
18 8254 timer initialization
08 Initialize PCIset registers with initial POST values
C4 Initialize system flags in CMOS
11 Load alternate registers with initial POST values
0E Initialize I/O
0C Initialize caches to initial POST values
16 BIOS ROM checksum
17 Turn off cache
28 Autosize DRAM
2A Clear 512KB base RAM
2C RAM failure on address line xxxx
2E RAM failure on data bits xxxx of low byte of memory bus (first 4 meg)
2F Initialize L2 cache if enabled in CMOS
38 Shadow system BIOS ROM
20 Test DRAM refresh
29 Post Memory Manager initialization (PMM)
33 Post Dispatch Manager initialization
34 Test CMOS
C1 Post error manager initialization
09 Set IN POST flag
0A Initialize processor registers and CPU microcode
3A Autosize cache
0B Enable processor cache
0F Initialize the local bus IDE
10 Initialize Power Management (APM not used in Nightshade)
14 Initialize keyboard controller
1A 8237 DMA controller initialization
1C Reset Programmable Interrupt Controller
22 Test 8742 Keyboard Controller
32 Read processor bus-clock frequency and compute boot processor speed
67 Initialize and register other CPU via SMM through APIC bus
69 Initialize SMI handler for all processors
00 Wait for secondary processor to execute init SMI handler
F4 Exit SMI handler (secondary processor executed halt in SMI)
3C Configure advanced PCIset registers and reset coprocessor
3D Load alternate registers with CMOS values
42 Initialize interrupt vectors
46 Check ROM copyright notice
45 Initialize all pre-PnP devices
49 Initialize PnP bus and devices (also read ESCD and allocate resources)
48 Check video configuration against CMOS (VGA or MDA)
4A Initialize all video adapters in system
4C Shadow video BIOS ROM
24 Put CPU in big real mode (flat mode memory addressing - up to 4GB)
59 Post display manager initialization (video screen error codes now visible)
22 Reset and test keyboard first try (only warm reset)
52 Reset and test keyboard controller (both warm and cold reset)
54 Set key click if enabled
76 Enable keyboard
58 Test for unexpected interrupts
4B QuietBoot start (not used in N440BX)
4E Display copyright notice
50 Display CPU(s) type and speed
51 EISA initialized (not used in N440BX)
5A Display prompt "Press F2 to enter SETUP"
5B Disable CPU L1 cache for memory test
5C Test RAM between 512KB and 640KB
60 Test extended memory (4MB to top of memory)
62 Test extended memory address lines
64 Jump to UserPatch1
66 Configure advanced cache registers
68 Enable external and processor caches
6A Display external cache size
6C Display shadow message
6E Display non-disposable segments
70 Display error messages to video
72 Check for configuration errors
74 Test real time clock
7C Setup hardware interrupt vectors
7E Test coprocessor if present
80 Not used
88 Initialize BIOS Data Area, time-outs for detecting parallel, serial and HDD controller. Clear CMOS shutdown flag
8A Initialize Extended BIOS Data Area
81 Late POST core initialization
87 Configure MCD devices
85 Initialize and detect PC compatible PnP ISA devices (serial, parallel, etc.)
82 Not used
84 Clear interrupts from COM port detection
86 Console redirection initialized
83 Configure onboard hard disk controller
89 Enable NMI
8C Initialize floppy controller
90 Initialize and detect hard disks
8B Detect and test for Mouse or Auxiliary device on keyboard controller
95 Install CD-ROM for boot
92 Jump to UserPatch2
C5 Initialize GPNV areas of DMI
98 Search for option ROMs. One long, two short beeps for checksum failure of an option ROM
93 Scan for User flash ROMs. MP Table initialization (wake up secondary processor and halt it)
9C Setup Power Management (not used)
9D Enable security
9E Enable hardware interrupts
A0 Set time of day
A2 Check key lock
A4 Initialize typematic rate
C2 Initialize DMI tables
C3 Log POST errors with POST Error Manager and to SEL in BMC. Update VID bits and memory presence to BMC. Display any FRB errors (watchdog time-outs, bist or CPU failures)
A8 Erase F2 prompt
AA Scan for F2 keystroke
AC Initialize EMP port if selected. Remove COM2 from BDA of EMP is enabled. Enter SETUP
AE Clear IN POST flag
B0 Turn on secure boot if enabled (secure front panel, blank video, floppy write protect). Check for errors
B2 POST done - prepare to boot Operating System
B4 One short beep before boot
B5 Display QuietBoot (not used)
BE Clear screen
B6 Check password (optional)
BC Clear parity checkers
BA Not used
B7 ACPI configuration (table configuration in memory and BDA)
BD Display MultiBoot menu if ESC is hit
BF Display system configuration summary (if enabled in CMOS)
8F Get total # of hard drives and put in BDA
91 Program IDE hard drives (timing, PIO modes, etc.)
9F Save total # of hard drives (SCSI and ATA) in BDA
97 Fixup MP Table (checksum)
99 Check SMART harddrive
C7 Prepare to boot OS, clean up graphics and PMM areas
C0 Try to boot Int19h. Return to video mode 3, disable PMM, return to real mode, disable gate A20, clear system memory, reset stack, invoke Int19h

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