Acer X1200 ED5200A - Aspire Service Manual

Contents

62 Chapter 412h 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 Reserved14h Program chipset default values into chipset. Chipset default values areMODBINable by OEM customers.15h Reserved16h Initial onboard clock generator if Early_Init_Onboard_Generator is defined. Seealso POST 26h.17h Reserved18h Detect CPU information including brand, SMI type (Cyrix or Intel) and CPU level(586 or 686).19h Reserved1Ah Reserved1Bh Initial interrupts vector table. If no special specified, all H/W interrupts are directedto SPURIOUS_INT_HDLR & S/W interrupts to SPURIOUS_soft_HDLR.1Ch Reserved1Dh Initial EARLY_PM_INIT switch.1Eh Reserved1Fh Load keyboard matrix (notebook platform)20h Reserved21h HPM initialization (notebook platform)22h Reserved23h 1 Check validity of RTC value: e.g. a value of 5Ah is an invalid value for RTCminute.2 Load CMOS settings into BIOS stack. If CMOS checksum fails, use default valueinstead.24h Prepare BIOS resource map for PCI & PnP use. If ESCD is valid, take intoconsideration of the ESCD’s legacy information.25h Early PCI Initialization:T Enumerate PCI bus numberT Assign memory & I/O resourceT Search for a valid VGA device & VGA BIOS, and put it into C000:026h 1 If Early_Init_Onboard_Generator is not defined Onboard clock generatorinitialization. Disable respective clock resource to empty PCI & DIMM slots.2 Init onboard PWM3 Init onboard H/W monitor devices27h Initialize INT 09 buffer28h Reserved29h 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 IDEcontroller. Measure CPU speed.2Ah Reserved2Bh Invoke Video BIOS2Ch ReservedPOST Code (Hex) POST Routine Description