Error Messages and Beep Codes 
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Table 40.  Port 80h POST Codes 
POST Code  Description of POST Operation 
  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 
  Chipset 
21  Initializing a chipset component 
  Memory 
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 
  PCI Bus 
50  Enumerating PCI busses 
51  Allocating resources to PCI bus 
52  Hot Plug PCI controller initialization 
53 – 57  Reserved for PCI Bus 
  USB 
58  Resetting USB bus 
59  Reserved for USB 
  ATA/ATAPI/SATA 
5A  Resetting PATA/SATA bus and all devices 
5B  Reserved for ATA 
  SMBus 
5C Resetting SMBus 
5D  Reserved for SMBus 
  Local Console 
70  Resetting the VGA controller 
71  Disabling the VGA controller 
72  Enabling the VGA controller 
  Remote Console 
78  Resetting the console controller 
79  Disabling the console controller 
7A  Enabling the console controller 
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