Nvidia 754 specifications Appendix C

Appendix

Appendix C

C-1 POST CODES

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)
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.
0B-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
10h	Auto detect flash type to load appropriate flash R/W codes into the run
	time area in F000 for ESCD & DMI support.
11h	Reserved
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 Early_Init_Onboard_Generator switch.
17h	Reserved

C-1