Port 80H Post Codes; Post Code Led Display - Intel BOXDP55SB Product Manual

Error Messages and Indicators

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 and displayed on the Desktop Board's seven-segment LED display shown
in Figure 34. This code is useful for determining the point where an error occurred
during the POST.
Figure 34. POST Code LED Display
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