4-6 Troubleshooting
Checkpoints 0
A checkpoint is either a byte or word value output to I/O port 80h. The BIOS outputs
checkpoints throughout boot-block and Power-On Self Test (POST) to indicate the task the
system is currently executing. Checkpoint share very useful in aiding software developers or
technicians in debugging problems that occur during the pre- boot process.
Viewing BIOS checkpoints 0
Viewing all checkpoints generated by the BIOS requires a checkpoint card, also referred to
as a POST card or POST diagnostic card. These are ISA or PCI add-in cards that show the
value of I/O port 80h on a LED display. Checkpoints may appear on the bottom right corner of
the screen during POST. This display method is limited, since it only displays checkpoints that
occur after the video card has been activated.
Bootblock Initialization Code Checkpoints 0
The Bootblock initialization code sets up the chipset, memory, and other components before
system is available. The following table describes the type of checkpoints that may occur
during the bootblock initialization portion of the BIOS.
Please note that checkpoints may differ between different platforms based on system
configuration. Checkpoints may change due to vendor requirements, system chipset or
option ROMs from add-in PCI devices.
SEC Status Codes
0
Table 4-2.
Checkpoint Description
0x00 Not Used
0x01 Power on. Reset type detection (soft/hard).
0x02 AP initialization before microcode loading
0x03 North Bridge initialization before microcode loading
0x04 South Bridge initialization before microcode loading
0x05 OEM initialization before microcode loading
0x06 Microcode loading
0x07 AP initialization after microcode loading
0x08 North Bridge initialization after microcode loading
0x09 South Bridge initialization after microcode loading
0x0A OEM initialization after microcode loading
0x0B Cache initialization
0x0C – 0x0D Reserved for future AMI SEC error codes
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