User`s manual
AIMB-220 
92 AIMB-220 User’s Manual 
40. POST Codes 
Please take reference to Phoenix-Award website for the latest post codes. 
http://www.phoenix.com/en/Customer+Services/BIOS/AwardBIOS/Award+Error+Codes.ht
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40.1 Normal POST Code 
Note: EISA POST codes are typically output to port address 300h. ISA POST codes are output to 
port address 80h.   
Code (hex)  Name  Description 
C0  Turn Off Chipset and 
CPU test 
OEM Specific-Cache control cache 
Processor Status (1FLAGS) Verification. Tests the following 
processor status flags: Carry, zero, sign, overflow, the BIOS sets 
each flag, verifies They are set, then turns each flag off and 
verifies it is off.   
Read/Write/Verify all CPU registers except SS, SP, and BP with 
data pattern FF and 00. RAM must be periodically refreshed to 
keep the memory from decaying. This function ensures that the 
memory refresh function is working properly. 
C1  Memory Presence  First block memory detect OEM Specific-Test to size on-board 
memory. Early chip set initialization Memory presence test OEM 
chip set routines clear low 64K of memory Test first 64K memory.
C2 Early Memory 
Initialization 
OEM Specific- Board Initialization 
C3  Extend Memory DRAM 
select 
OEM Specific- Turn on extended memory Initialization 
Cyrix CPU initialization, Cache initialization 
C4 Special Display 
Handling 
OEM Specific- Display/Video Switch handling so that switch 
handling display switch errors never occurs 
C5  Early Shadow  OEM specific- Early shadow enable for fast boot 
C6  Cache presence test  External cache size detection 
CF  CMOS Check  CMOS checkup 
B0  Spurious  If interrupt occurs in protected mode. 
B1  Unclaimed NMI  If unmasked NMI occurs, display Press F1 to disable NMI, F2 
reboot. 
BF  Program Chip Set  To program chipset from defaults values 
E1-EF  Setup Pages  E1- Page 1, E2 - Page 2, etc. 
1  Force load Default to 
chipset 
Chipset defaults program 
2 Reserved   










