Specifications

Appendix B: POST Code Diagnostic LED Decoder
Revision 1.3
Intel order number E44588-003
46
Diagnostic LED Decoder
O = On, X=Off
Upper Nibble Lower Nibble
MSB LSB
Checkpoint
8h 4h 2h 1h 8h 4h 2h 1h
LED #7 #6 #5 #4 #3 #2 #1 #0
Description
0x52h X O X O X X O X Hot Plug PCI controller initialization
0x53h X O X O X X O O Reserved for PCI bus
0x54h X O X O X O X X Reserved for PCI bus
0x55h X O X O X O X O Reserved for PCI bus
0X56h X O X O X O O X Reserved for PCI bus
0x57h X O X O X O O O Reserved for PCI bus
USB
0x58h X O X O O X X X Resetting USB bus
0x59h X O X O O X X O Reserved for USB devices
ATA/ATAPI/SATA
0x5Ah X O X O O X O X Resetting SATA bus and all devices
0x5Bh X O X O O X O O Reserved for ATA
SMBUS
0x5Ch X O X O O O X X Resetting SMBUS
0x5Dh X O X O O O X O Reserved for SMBUS
Local Console
0x70h X O O O X X X X Resetting the video controller (VGA)
0x71h X O O O X X X O Disabling the video controller (VGA)
0x72h X O O O X X O X Enabling the video controller (VGA)
Remote Console
0x78h X O O O O X X X Resetting the console controller
0x79h X O O O O X X O Disabling the console controller
0x7Ah X O O O O X O X Enabling the console controller
Keyboard (only USB)
0x90h O X X O X X X X Resetting the keyboard
0x91h O X X O X X X O Disabling the keyboard
0x92h O X X O X X O X Detecting the presence of the keyboard
0x93h O X X O X X O O Enabling the keyboard
0x94h O X X O X O X X Clearing keyboard input buffer
0x95h O X X O X O X O Instructing keyboard controller to run Self Test(PS/2 only)
Mouse (only USB)
0x98h O X X O O X X X Resetting the mouse
0x99h O X X O O X X O Detecting the mouse
0x9Ah O X X O O X O X Detecting the presence of mouse
0x9Bh O X X O O X O O Enabling the mouse
Fixed Media
0xB0h O X O O X X X X Resetting fixed media device
0xB1h O X O O X X X O Disabling fixed media device
0xB2h O X O O X X O X
Detecting presence of a fixed media device (hard drive detection,
and so forth.)
0xB3h O X O O X X O O Enabling / configuring a fixed media device
Removable Media
0xB8h O X O O O X X X Resetting removable media device
0xB9h O X O O O X X O Disabling removable media device
0xBAh O X O O O X O X
Detecting presence of a removable media device (CD-ROM
detection, and so forth.)
0xBCh O X O O O O X X Enabling / configuring a removable media device
Boot Device Selection (BDS)
0xD0 O O X O X X X X Trying to boot device selection 0
0xD1 O O X O X X X O Trying to boot device selection 1
0xD2 O O X O X X O X Trying to boot device selection 2
0xD3 O O X O X X O O Trying to boot device selection 3
0xD4 O O X O X O X X Trying to boot device selection 4