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BIOS PostCodes

Intel Motherboards:

Intel D810MO BIOS Post Codes:

Uncompressed INIT Code Checkpoints:

D0 NMI is disabled. Onboard keyboard controller and real time clock enabled (if present). Initialization code checksum verification starting
D1 Keyboard controller BAT test, CPU ID saved, and going to 4GB flat mode
D3 Initialize chipset, start memory refresh, and determine memory size
D4 Verify base memory
D5 Initialization code to be copied to segment 0 and control to be transferred to segment 0
D6 Control is in segment 0. Used to check if in recovery mode and to verify main BIOS checksum. If in recovery mode or if main BIOS checksum is wrong, go to checkpoint E0 for recovery. Othewise, got o checkpoint D7 to give control to main BIOS
D7 Find maain BIOS module in ROM image
D8 Uncompress the main BIOS module
D9 Copy main BIOS image to F000 shadow RAM and give control to main BIOS in F000 shadow RAM

Boot Block recovery Code Check Points:

E0 Onboard diskette controller (if any) is initialized. Compressed recovery code is uncompressed at F000:0000 in shadow RAM. Give control to recovery code at F000 in shadow RAM. Initialize interrupt vector tables, system timer, DMA controller, and interrupt controller
E8 Initialize extra (Intel recovery) module
E9 Initialize diskette drive
EA Try to boot from diskette. If reading of boot sector is successful, give control to boot sector code
EB Boot from diskette failed; look for ATAPI (LS-120, Zip) devices
EC Try to boot from ATAPI device. If reading of boot sector is successful, give control to boot sector code
EF Boot from diskette and ATAPI device failed. Give two beeps. Retry the booting procedure (go to checkpoint E9)

Runtime Code Uncompressed in F000 Shadow RAM:

03 NMI is disabled. To check soft reset/power on
05 BIOS stack set. Going to disable cache if any
06 POST code to be uncompressed
07 CPU init and CPU data area init to be done
08 CMOS checksum calculation to be done next
0B Any initialization before keyboard BAT to be done next
0C Keyboard controller I/B free. To issure the BAT command to the keyboard controller
0E Any initialization after keyboard controller BAT to be done next
0F Keyboard command byte written
10 Going to issue Pin 23, 24 blocking/unblocking command
11 Going to check pressing of <INS>, <END> key during power-on
12 To init CMOS if "Init CMOS in every boot" is set or <END> key is pressed. Going to disable DMA and interrupt controllers
13 Video display is disabled and port B is initialized. Chipset init about to begin
14 8254 timer test about to start
19 About to start memory refresh test
1A Memory refresh line is toggling. Going to check 15 µs On/OFF time
23 To read 8042 input port and disable megakey GreenPC feature. make BIOS cade segment writeable
24 To do any setup before int vector init
25 Interrupt vector initialization to begin. To clear password if necessary
27 Any initialization before setting video mode to be done
28 Going for monochrome mode and color mode setting
2A Different buses init (system, static, output devices) to start if present
2B To give control for any setup required before optional ROM check
2C To look for optional video ROM and give control
2D To give control to do any processing after video ROM returns control
2E If EGA/VGA not found then do display memory R/W
2F EGA/VGA not found. Display memory R/W test about to begin
30 Display memoryR/W test passed. About to look for the retrace checking
31 Display memory R/W test or retrace checking failed. To do alternate Display memory R/W test
32 Alternate Disaply memory R/W test passed. To look for the alternate display retrace checking
34 Video display checking over. Display mode to be set next
37 Display mode set. Going to display the power on message
38 Different buses init (input, IPL, general devices) to start if present
39 Display different buses initialization error messages
3A New cursor position read and saved. To display the Hit <DEL> message
40 tp prepare the descriptor tables
42 To enter virtual mode for memory test
43 To enable interrupts for diagnostics mode
44 To initialize data to check memory wrap around at 0:0
45 Data initializaed. Going to check for memory wrap around at 0:0 and finding the total system test memory
46 Memory wrap around test done. Memory size calculation over. About to go for writing patterns to test memory.
47 Pattern to be tested written in extended memory. Going to write patterns in base 640KB memory
48 Patterns written in base memory. Going to find out amount of memory below 1M memory
49 Amount of memory below 1M found and verified. Going to find out amount of memory above 1M memory
4B Amount of memory above 1M found and verified. Check for soft reset and going to clear memory below 1M for soft reset. (If power on, go to check point # 4E
4C Memory below 1M cleared. (SOFT RESET) Going to clear memory above 1M
4D memory above 1M cleared (SOFT RESET) Going to save the memory size (Go to checl point # 52
4E Memory test started. (NOT SOFT RESET) About to display the first 64KB memory size
4F Memory size display started. this will be updated during memory test. going for sequential and random memory test
50 Memory testing/iniialization below 1MB complete. Going to adjust displayed memory size for relocation shadow
51 Memory size display adjusted due to relocation/shadow. memory test above 1MB to follow
52 Memory testing/initialization above 1MB complete. Going to save memory size information
53 Memory size information is saved. CPU registers are saved. Going to enter real mode
54 Shutdown successful, CPu in real mode. Going to disable gate A20 line and disable parity/NMI
57 A20 address line, parity/NMI disable successful. Going to adjust memory size depending on relocation/shadow
58 Memory size adjusted for relocation/shadow. Going to clear hit <DEL> message
59 Hit <DEL> message cleared. <WAIT...> message displayed. About to start DMA and interrupt controller test
60 DMA page register test passed. To do DMA #1 base register test
62 DMA #1 base register test passed. To do DMA #2 base register test
65 DMA #2 base register test passed. To program DMA #1 and #2
66 DMA #1 and #2 programming over. To initialize 8259 interrupt controller
7F Extended NMI sources enabling is in progress
80 Keyboard test started. Clearing output buffer, checking for stuck key, to issue keyboard reset command
81 Keyboard reset error/stuck key found. To issue keyboard controller interface test command
82 Keyboard controller interface test over. To write command byte and init circular buffer
83 Command byte written, global data init done. To check for lock-key
84 Lock key checking over. to check for memory size mismatch with CMOS
85 Memory size check done. to display soft error and check for password or bypass setup
86 Passwoed checked. About to do programming before setup
87 Programming before setup complete. To uncompress SETUP code and execute CMOS setup
88 Returned from CMOS setup program and screen is cleared. About to do programming after setup
89 Programming after setup complete. Going to display power-on screen message
8B First screen message displayed. <WAIT...> message displayed. PS/2 mouse check and extended BIOS data area allocation to be done
8C Setup options programming after CMOS setup about to start
8D Going to hard disk controller reset
8F Hard disk controller reset done. Floppy setup to be done next
91 Floppy setup complete. Hard disk setup to be done next
95 Init of different buses optional ROMs from C800 to start.
96 Going to do any init before C800 optional ROM control
97 Any init before C800 optional ROM control is over. Optional ROM check and control will be done next
98 Optional ROM control is done. About to give control to do any required processing after optional ROM returns control and enable external cache
99 Any initialization required after optional ROM test over. Going to setup timer data area and printer base address
9A Return after setting timer and printer base addresses. Going to set the RS-232 base address
9B Returned after RS-232 base address. Going to do any initialization before coprocessor test
9C Required initialization before coprocessor is over. Going to initializae the coprocessor test
9D Coprocessor initialized. Goin to do any initialization after coprocessor test
9E Initialization after coprocessor test is complete. Goin to check extended keyboard, keyboard ID and num-lock
A2 Going to display any soft errors
A3 Soft error display complete. Going to set keyboard typematic rate
A4 Keyboard typematic rate set. To program memory wait states
A5 Going to enable parity/NMI
A7 NMI and parity enabled. Going to do any initialization required before giving control to optional ROM at E000
A8 Initialization before E000 ROM control over. E000 ROM to get control next
A9 Returned from E000 ROM control. Going to do any initialization required after E000 optional ROM control
AA Initialization after E000 optional ROM control is over. Going to display the system configuration
AB Put Int13 module runtime image to shadow
AC Generate MP for multiprocessor support (if present)
AD Put CGA Int10 module (if present) in shadow
AE Uncompress SMBIOS module and init SMBIOS code and form the runtime SMBIOS image in shadow
B1 Going to copy any code to specific area
00 Copying of code to specific area done. Going to give control to Int19 boot loader



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