Table 68. Uncompressed Init Code Checkpoints; Port 80H Post Codes - Intel S875WP1LX Specification

S875WP1-E TPS
Error Message
Off Board Parity Error
On Board Parity Error
Parity Error
NVRAM/CMOS/PASSWORD cleared by
Jumper
<CTRL_N> Pressed
8.2.2

Port 80h POST Codes

During the POST, the BIOS generates diagnostic progress codes (POST codes) to I/O port 80h.
If the POST fails, execution stops and the last POST code generated is left at port 80h. This
code is useful for determining the point where an error occurred.
Displaying the POST codes requires a PCI bus add-in card, often called a POST card. The
POST card can decode the port and display the contents on a medium such as a seven-
segment display.
The tables below offer descriptions of the POST codes generated by the BIOS. Table 68
defines the uncompressed INIT code checkpoints, Table 69 describes the boot block recovery
code checkpoints, and Table 70 lists the runtime code uncompressed in F000 shadow RAM.
Some codes are repeated in the tables because that code applies to more than one operation.

Table 68. Uncompressed INIT Code Checkpoints

Code
D0 NMI is Disabled. Onboard KBC, RTC enabled (if present). Init code Checksum verification starting.
D1 Keyboard controller BAT test, CPU ID saved, and going to 4 GB flat mode.
D3 Do necessary chipset initialization, start memory refresh, and do memory sizing.
D4 Verify base memory.
D5 Init code to be copied to segment 0 and control to be transferred to segment 0.
D6 Control is in segment 0. To check recovery mode and verify main BIOS checksum. If either it is recovery
mode or main BIOS checksum is bad, go to check point E0 for recovery else go to check point D7 for giving
control to main BIOS.
D7 Find Main BIOS module in ROM image.
D8 Uncompress the main BIOS module.
D9 Copy main BIOS image to F000 shadow RAM and give control to main BIOS in F000 shadow RAM.
Revision 4.0
Explanation
A parity error occurred on an off-board card. This error is followed by an
address.
A parity error occurred in on-board memory. This error is followed by an
address.
A parity error occurred in on-board memory at an unknown address.
NVRAM, CMOS, and passwords have been cleared. The system
should be powered down and the jumper removed.
CMOS is ignored and NVRAM is cleared. User must enter Setup.
Description of POST Operation
Error Reporting and Handling
89