User`s guide

Error and Informational Messages
111
POST Codes and Countdown Codes
The BIOS indicates the current testing phase during POST after the video adapter has
been successfully initialized by outputting a 2-digit hex code to I/O location 80h. If a
port-80hISA POST boardis installed, itdisplays the2-digit codeon apair ofhex display
LEDs, see Table 4-1.
Table 4-1 Port-80 Codes
Normal Port 80
Codes
Beeps Error
02 Verify Real Mode
04 Get processor type
06 Initialize system hardware
08 Initialize chipset registers with initial POST values
09 Set in POST flag
0A Initialize processor registers
0B Enable processor cache
0C Initialize caches to initial POST values
0E Initialize I/O
0F Initialize the local bus IDE
10 Initialize Power Management
11 Load alternate registers with initial POST valuesnew
12 Restore processor control word during warm boot
14 Initialize keyboard controller
16 1-2-2-3 BIOS ROM checksum
18 8254 timer initialization
1A 8237 DMA controller initialization
1C Reset Programmable Interrupt Controller
20 1-3-1-1 Test DRAM refresh