Intel GA-G1975X - Manual (Page 105)

Appendix - 105 -
English
POST (hex) Description
1Dh Initial EARLY_PM_INIT switch.
1Fh Load keyboard matrix (notebook platform)
21h HPM initialization (notebook platform)
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.
3. Prepare BIOS resource map for PCI & PnP use. If ESCD is
valid, take into consideration of the ESCD¡¦s legacy information.
4. Onboard clock generator initialization. Disable respective clock
resource to empty PCI & DIMM slots.
5.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.
25h PCI Bus Initialization
26h Init clock Generator
27h Initialize INT 09 buffer
29h 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.
4. Measure CPU speed
2Bh Invoke video BIOS.
2Dh 1. Initialize multi-language
2. Put information on screen display, including Award title, CPU type,
CPU speed ......
33h Reset keyboard except Winbond 977 series Super I/O chips.
3Ch Test 8254
3Eh Test 8259 interrupt mask bits for channel 1.
40h Test 8259 interrupt mask bits for channel 2.
43h Test 8259 functionality.
47h Initialize EISA slot
49h 1. Calculate total memory by testing the last double word of each 64K page.
2. Program write allocation for AMD K5 CPU 64K page.
4Eh 1. Program MTRR of M1 CPU
2. Initialize L2 cache for P6 class CPU & program CPU with proper
cacheable range.
3. Initialize the APIC for P6 class CPU.
4. On MP platform, adjust the cacheable range to smaller one in case the
cacheable ranges between each CPU are not identical.