POST Code (Hex)
Use walking 1's algorithm to check out interface in CMOS circuitry. Also set real-
time clock power status, and then check for override.
Program chipset default values into chipset. Chipset default values are
MODBINable by OEM customers.
Initial onboard clock generator if Early_Init_Onboard_Generator is defined. See
also POST 26h.
Detect CPU information including brand, SMI type (Cyrix or Intel) and CPU level
(586 or 686).
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.
Initial EARLY_PM_INIT switch.
Load keyboard matrix (notebook platform)
HPM initialization (notebook platform)
1 Check validity of RTC value: e.g. a value of 5Ah is an invalid value for RTC
2 Load CMOS settings into BIOS stack. If CMOS checksum fails, use default value
Prepare BIOS resource map for PCI & PnP use. If ESCD is valid, take into
consideration of the ESCD's legacy information.
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
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
Initialize INT 09 buffer
1 Program CPU internal MTRR (P6 & PII) for 0-640K memory address.
2 Initialize the APIC for Pentium class CPU.
3 Program early chipset according to CMOS setup. Example: onboard IDE
controller. Measure CPU speed.
Invoke Video BIOS
POST Routine Description