POST Codes Tables
These tables describe the chipset and core POST codes, functions, phases, and components for the POST.
Chipset POST Codes
The following table details the chipset POST codes and functions used in the POST.
Code | Beeps | POST Routine Description |
|
|
|
02h |
| Verify Real Mode |
|
|
|
03h |
| Disable |
|
|
|
04h |
| Get CPU type |
|
|
|
06h |
| Initialize system hardware |
|
|
|
08h |
| Initialize chipset with initial POST values |
|
|
|
09h |
| Set IN POST flag |
|
|
|
0Ah |
| Initialize CPU registers |
|
|
|
0Bh |
| Enable CPU cache |
|
|
|
0Ch |
| Initialize caches to initial POST values |
|
|
|
0Eh |
| Initialize I/O component |
|
|
|
0Fh |
| Initialize the local bus IDE |
|
|
|
10h |
| Initialize Power Management |
|
|
|
11h |
| Load alternate registers with initial POST values |
|
|
|
12h |
| Restore CPU control word during warm boot |
|
|
|
13h |
| Initialize PCI Bus Mastering devices |
|
|
|
14h |
| Initialize keyboard controller |
|
|
|
16h | BIOS ROM checksum | |
|
|
|
17h |
| Initialize cache before memory autosize |
|
|
|
18h | 8254 | timer initialization |
|
|
|
1Ah | 8237 | DMA controller initialization |
|
|
|
1Ch |
| Reset Programmable Interrupt Controller |
|
|
|
20h | Test DRAM refresh | |
|
|
|
22h | Test 8742 Keyboard Controller | |
|
|
|
24h |
| Set ES segment register to 4 GB |
|
|
|
26h |
| Enable A20 line |
|
|
|
28h |
| Autosize DRAM |
|
|
|
29h |
| Initialize POST Memory Manager |
|
|
|
2Ah |
| Clear 512 KB base RAM |
|
|
|
2Ch | RAM failure on address line xxxx* | |
|
|
|
2Eh | RAM failure on data bits xxxx* of low byte of memory bus | |
|
|
|
2Fh |
| Enable cache before system BIOS shadow |
|
|
|
30h | RAM failure on data bits xxxx* of high byte of memory bus | |
|
|
|
32h |
| Test CPU |
|
|
|
33h |
| Initialize Phoenix Dispatch Manager |
|
|
|
36h |
| Warm start shut down |
|
|
|
38h |
| Shadow system BIOS ROM |
|
|
|
3Ah |
| Autosize cache |
|
|
|
Chapter 4 | 141 |