Desktop Boards
Desktop Boards
Port 80h POST Codes

This document defines the beep codes, error messages, and POST codes associated with BIOS versions based on Extensible Framework Interface (EFI).

Beep codes
BIOS error messages
Port 80h POST codes
Displaying POST codes
POST code ranges
POST codes
Typical POST sequence

Beep codes
The onboard speaker emits audible error codes (beep codes) during POST. Not all Intel® Desktop Boards include an onboard speaker.

Type Pattern Frequency
Memory error Three long beeps 1,280 Hz
Thermal warning Four alternating beeps:
High tone, low tone, high tone, low tone
High tone: 2,000 Hz
Low tone: 1,600 Hz

BIOS error messages

Error message Explanation
A processor that was not meant to be used with this board has been detected. Using an unsupported processor can result in improper operation, damage to the desktop board or processor or reduced product life. System shuts down in 10 seconds. The installed processor is not compatible with the desktop board.
CMOS Battery Low The battery could be losing power. Replace the battery soon.
CMOS Checksum Bad The CMOS checksum is incorrect. CMOS memory can be corrupted. Run Setup to reset values.
Memory Size Decreased Memory size has decreased since the last boot. If no memory was removed, the memory might be bad.
No Boot Device Available System did not find a device to boot.

Port 80h POST codes
During the Power-On Self Test (POST), the BIOS sends progress codes (POST codes) to I/O port 80h. If the POST fails, the last POST code generated is left at port 80h. This code can be used to find out why the error occurred.

Displaying POST codes
You can display POST codes using either of the following methods.

POST card (PCI add-in card) The POST card decodes the port and displays the contents on an LED display. The POST card must be installed in PCI bus connector 1.
Onboard POST code LED display Some Intel® Desktop Boards include an onboard LED to show POST codes

Port 80h POST code ranges
In the tables below, all POST codes and range values are listed in hexadecimal.

Range Category/Subsystem
00 – 0F Debug codes: Can be used by any PEIM/driver for debug
10 – 1F Host Processors
20 – 2F Memory/Chipset
30 – 3F Recovery
40 – 4F Reserved for future use
50 – 5F I/O Busses: PCI, USB, ISA, ATA, etc.
60 – 6F Not currently used
70 – 7F Output Devices: All output consoles
80 – 8F Reserved for future use (new output console codes)
90 – 9F Input devices: Keyboard/Mouse
A0 – AF Reserved for future use (new input console codes)
B0 – BF Boot Devices: Includes fixed media and removable media.
C0 – CF Reserved for future use
D0 – DF Boot device selection
E0 – FF E0 - EE: Miscellaneous codes
F0 – FF: FF processor exception

Port 80h POST codes

POST code Description of POST operation
00 - 0F Debug Codes: can be used by any PEIM/driver for debug
10 - 1F Host Processor
10 Power-on initialization of the host processor (Boot Strap Processor)
11 Host processor Cache initialization (including APs)
12 Starting Application processor initialization
13 SMM initialization
14 LAN initialization
15 Exit early platform init driver
16 SMBUS driver initialization
17 Entry to SMBUS execute read/write
19 Entry to CK505 programming
1F Unrecoverable CPU error
20 - 2F Memory / Chipset
21 Initializing a chipset component
22 Reading SPD from memory DIMMs
23 Detecting presence of memory DIMMs
24 Programming timing parameters in the memory controller and the DIMMs
25 Configuring memory
26 Optimizing memory settings
27 Initializing memory, such as ECC init
28 Testing memory
2F No memory detected or no useful memory detected
30 - 3F Recovery
30 Crisis Recovery has initiated per User request
31 Crisis Recovery has initiated by software (corrupt flash)
34 Loading recovery capsule
35 Handing off control to the recovery capsule
3F Unable to recover
50 - 5F I/O Busses (PCI, USB, ISA, ATA, etc.)
50 Enumerating PCI busses
51 Allocating resources to PCI bus
52 Hot Plug PCI controller initialization
53 – 57 Reserved for PCI Bus
58 Resetting USB bus
59 Reserved for USB
5A Resetting PATA/SATA bus and all devices
5B Reserved for ATA
5C Resetting SMBUS
5D Reserved for SMBUS
5F Unrecoverable I/O bus error
60 - 6F

There are currently no valid POST codes in the 60 - 6F range.

If you see a POST code in this range, it should be read as B0 - BF. (On a 7-segment LED display, the 'b' looks like a 6).


70 - 7F Output Devices
70 Resetting the VGA controller
71 Disabling the VGA controller
72 Enabling the VGA controller
78 Resetting the console controller
79 Disabling the console controller
7A Enabling the console controller
7F Unrecoverable output device error
90 - 9F Input Devices
90 Resetting keyboard
91 Disabling keyboard
92 Detecting presence of keyboard
93 Enabling the keyboard
94 Clearing keyboard input buffer
95 Instructing keyboard controller to run Self Test (PS2 only)
98 Resetting mouse
99 Disabling mouse
9A Detecting presence of mouse
9B Enabling mouse
9F Unrecoverable input device (keyboard or mouse) error
B0 - BF Boot Devices
B0 Resetting fixed media
B1 Disabling fixed media
B2 Detecting presence of a fixed media (IDE hard drive detection etc.)
B3 Enabling/configuring a fixed media
B8 Resetting removable media
B9 Disabling removable media
BA Detecting presence of a removable media (IDE, CD-ROM detection, etc.)
BC Enabling/configuring a removable media
BF Unrecoverable boot device error
D0 - DF Boot Device Selection
Dy Trying boot selection y (y=0 to 15)
E0 - FF Miscellaneous Codes
E0 Started dispatching PEIMs (emitted on first report of EFI_SW_PC_INIT_BEGIN EFI_SW_PEI_PC_HANDOFF_TO_NEXT)
E2 Permanent memory found
E1, E3 Reserved for PEI/PEIMs
E4 Entered DXE phase
E5 Started dispatching drivers
E6 Started connecting drivers
E7 Waiting for user input
E8 Checking password
E9 Entering BIOS setup
EB Calling Legacy Option ROMs
EF Boot/S3 resume failure
F4 Entering Sleep state
F5 Exiting Sleep state
F8 EFI boot service ExitBootServices ( ) has been called
F9 EFI runtime service SetVirtualAddressMap ( ) has been called
FA EFI runtime service ResetSystem ( ) has been called
FF Processor exception

Typical port 80h POST sequence
Port 80h code values typically increase during the boot process. The early codes are for subsystems closer to the processor and the later codes are for peripherals. Generally, the order of initialization is Processor -> Memory -> Busses -> Output/Input Devices -> Boot Devices. The sequence of POST is system-specific.

POST code Description
21 Initializing a chipset component
22 Reading SPD from memory DIMMs
23 Detecting presence of memory DIMMs
25 Configuring memory
28 Testing memory
34 Loading recovery capsule
E4 Entered DXE phase
12 Starting Application processor initialization
13 SMM initialization
50 Enumerating PCI busses
51 Allocating resourced to PCI bus
92 Detecting the presence of the keyboard
90 Resetting keyboard
94 Clearing keyboard input buffer
95 Keyboard Self Test
EB Calling Video BIOS
58 Resetting USB bus
5A Resetting PATA/SATA bus and all devices
92 Detecting the presence of the keyboard
90 Resetting keyboard
94 Clearing keyboard input buffer
5A Resetting PATA/SATA bus and all devices
28 Testing memory
90 Resetting keyboard
94 Clearing keyboard input buffer
E7 Waiting for user input
01 INT 19
00 Ready to boot

This applies to:

Intel® Desktop Board D2500CC
Intel® Desktop Board D2500HN
Intel® Desktop Board D2550DC2
Intel® Desktop Board D2550MUD2
Intel® Desktop Board D2700DC
Intel® Desktop Board D2700MUD
Intel® Desktop Board D410PT
Intel® Desktop Board D425KT
Intel® Desktop Board D510MO
Intel® Desktop Board D525MW
Intel® Desktop Board DB65AL
Intel® Desktop Board DB75EN
Intel® Desktop Board DB85FL
Intel® Desktop Board DH55HC
Intel® Desktop Board DH55PJ
Intel® Desktop Board DH55TC
Intel® Desktop Board DH57DD
Intel® Desktop Board DH57JG
Intel® Desktop Board DH61AG
Intel® Desktop Board DH61AGL
Intel® Desktop Board DH61BE
Intel® Desktop Board DH61BF
Intel® Desktop Board DH61CR
Intel® Desktop Board DH61DL
Intel® Desktop Board DH61HO
Intel® Desktop Board DH61KVCH
Intel® Desktop Board DH61SA
Intel® Desktop Board DH61SKCH
Intel® Desktop Board DH61WW
Intel® Desktop Board DH61ZE
Intel® Desktop Board DH67BL
Intel® Desktop Board DH67CF
Intel® Desktop Board DH67CL
Intel® Desktop Board DH67GD
Intel® Desktop Board DH67VR
Intel® Desktop Board DH77DF
Intel® Desktop Board DH77EB
Intel® Desktop Board DH77KC
Intel® Desktop Board DH87MC
Intel® Desktop Board DH87RL
Intel® Desktop Board DN2800MT
Intel® Desktop Board DP55KG
Intel® Desktop Board DP55SB
Intel® Desktop Board DP55WB
Intel® Desktop Board DP55WG
Intel® Desktop Board DP67BA
Intel® Desktop Board DP67BG
Intel® Desktop Board DP67DE
Intel® Desktop Board DQ57TM
Intel® Desktop Board DQ57TML
Intel® Desktop Board DQ67EP
Intel® Desktop Board DQ67OW
Intel® Desktop Board DQ67SW
Intel® Desktop Board DQ77CP
Intel® Desktop Board DQ77KB
Intel® Desktop Board DQ77MK
Intel® Desktop Board DQ87PG
Intel® Desktop Board DX58OG
Intel® Desktop Board DX58SO
Intel® Desktop Board DX58SO2
Intel® Desktop Board DX79SI
Intel® Desktop Board DX79SR
Intel® Desktop Board DX79TO
Intel® Desktop Board DZ68AF
Intel® Desktop Board DZ68BC
Intel® Desktop Board DZ68DB
Intel® Desktop Board DZ68PL
Intel® Desktop Board DZ68ZV
Intel® Desktop Board DZ75ML-45K
Intel® Desktop Board DZ77BH-55K
Intel® Desktop Board DZ77GA-70K
Intel® Desktop Board DZ77RE-75K
Intel® Desktop Board DZ77SL-50K
Intel® Desktop Board DZ87KLT-75K

Solution ID: CS-025434
Last Modified: 01-Oct-2014
Date Created: 21-Jan-2007
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