POST Code (Hex) | POST Routine Description |
|
|
12h | Use walking 1’s algorithm to check out interface in CMOS circuitry. Also set real- |
| time clock power status, and then check for override. |
|
|
13h | Reserved |
|
|
14h | Program chipset default values into chipset. Chipset default values are |
| MODBINable by OEM customers. |
|
|
15h | Reserved |
|
|
16h | Initial onboard clock generator if Early_Init_Onboard_Generator is defined. See |
| also POST 26h. |
|
|
17h | Reserved |
|
|
18h | Detect CPU information including brand, SMI type (Cyrix or Intel) and CPU level |
| (586 or 686). |
|
|
19h | Reserved |
|
|
1Ah | Reserved |
|
|
1Bh | Initial interrupts vector table. If no special specified, all H/W interrupts are directed |
| to SPURIOUS_INT_HDLR & S/W interrupts to SPURIOUS_soft_HDLR. |
|
|
1Ch | Reserved |
|
|
1Dh | Initial EARLY_PM_INIT switch. |
|
|
1Eh | Reserved |
|
|
1Fh | Load keyboard matrix (notebook platform) |
|
|
20h | Reserved |
|
|
21h | HPM initialization (notebook platform) |
|
|
22h | Reserved |
|
|
23h | 1 Check validity of RTC value: e.g. a value of 5Ah is an invalid value for RTC |
| minute. |
| 2 Load CMOS settings into BIOS stack. If CMOS checksum fails, use default value |
| instead. |
|
|
24h | Prepare BIOS resource map for PCI & PnP use. If ESCD is valid, take into |
| consideration of the ESCD’s legacy information. |
|
|
25h | Early PCI Initialization: |
| Enumerate PCI bus number |
| Assign memory & I/O resource |
| Search for a valid VGA device & VGA BIOS, and put it into C000:0 |
|
|
26h | 1 If Early_Init_Onboard_Generator is not defined Onboard clock generator |
| initialization. Disable respective clock resource to empty PCI & DIMM slots. |
| 2 Init onboard PWM |
| 3 Init onboard H/W monitor devices |
|
|
27h | Initialize INT 09 buffer |
|
|
28h | Reserved |
|
|
29h | 1 Program CPU internal MTRR (P6 & PII) for |
| 2 Initialize the APIC for Pentium class CPU. |
| 3 Program early chipset according to CMOS setup. Example: onboard IDE |
| controller. Measure CPU speed. |
|
|
2Ah | Reserved |
|
|
2Bh | Invoke Video BIOS |
|
|
2Ch | Reserved |
|
|
62 | Chapter 4 |