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Embedded Intel® Atom™ Processor N2800 with Intel® NM10 Express Chipset Development Kit User's Manual
5.5
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 POST card that can interface with the Debug
header. The POST card can decode the port and display the contents on a medium
such as a seven-segment display. Refer to the location of the Debug header in
Figure 1.
The following tables provide information about the POST codes generated by the BIOS:
Table 50 lists the Port 80h POST code ranges
Table 51 lists the Port 80h POST codes themselves
Table 52 lists the Port 80h POST sequence
NOTE
In the tables listed above, all POST codes and range values are listed in hexadecimal.
Table 50. Port 80h POST Code Ranges
Range
0x00 – 0x05
0x10, 0x20, 0x30
0x11 – 0x1F
0x21 – 0x29
0x2A – 0x2F
0x31 – 0x35
0x36 – 0x3F
0x41 – 0x4F
0x50 – 0x5F
0x60 – 0x6F
0x70 – 0x7F
0x80 – 0x8F
0x90 – 0x9F
0xA0 – 0xAF
0xB0 – 0xBF
0xC0 – 0xCF
0xD0 – 0xDF
Subsystem
Entering SX states S0 to S5.
Resuming from SX states (0x10 –0x20 – S2, 0x30 – S3, etc.)
PEI phase pre MRC execution
MRC memory detection
PEI phase post MRC execution
Recovery
Platform DXE driver
CPU Initialization (PEI, DXE, SMM)
I/O Buses: PCI, USB, ATA etc. 0x5F is an unrecoverable error. Start with PCI.
BDS
Output devices: All output consoles.
For future use
Input devices: Keyboard/Mouse.
For future use
Boot Devices: Includes fixed media and removable media. Not that critical since
consoles should be up at this point.
For future use
For future use
94
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