4-5
System Resources
• Check Point List
POST (hex) Description
CFh Test CMOS R/W functionality.
C0h Early chipset initialization:
-Disable shadow RAM
-Disable L2 cache (socket 7 or below)
-Program basic chipset registers
C1h Detect memory
-Auto-detection of DRAM size, type and ECC.
-Auto-detection of L2 cache (socket 7 or below)
A1h Set Initial Conditions (Default Values) in EBP
A2h Determine FSB frequency.
A3h Begin Detection of installed DIMMS
A4h Check for Column Latency
A5h 200Mhz or 266Mhz
A6h Check for tRAS timing
A7h Check for tRP timing
A8h Check for tRCD timing
A9h Check for ECC Support
AAh Check for refresh timing
ABh Verify that the DIMM's are in matched pairs
C3h Expand compressed BIOS code to DRAM
C5h Call chipset hook to copy BIOS back to E000 & F000 shadow
RAM.
01h Expand the Xgroup codes locating in physical address 1000:0
02h Reserved
03h Initial Superio_Early_Init switch.
04h Reserved
05h 1. Blank out screen
2. Clear CMOS error flag
06h Reserved
07h 1. Clear 8042 interface
2. Initialize 8042 self-test
08h 1. Test special keyboard controller for Winbond 977 series Super
I/O chips.
2. Enable keyboard interface.
09h Reserved
0Ah 1. Disable PS/2 mouse interface (optional).
2. Auto detect ports for keyboard & mouse followed by a port & interface swap
(optional).
3. Reset keyboard for Winbond 977 series Super I/O chips.
0Bh Reserved
0Ch Reserved
0Dh Reserved
0Eh Test F000h segment shadow to see whether it is R/W-able or not. If
test fails, keep beeping the speaker.
0Fh Reserved
