Onboard Indicators; Post Code Displayer - Abit AX78 User Manual

1.9 Onboard Indicators

1.9.1 POST Code Displayer

This is an LED device to display the "POST" Code, the acronym for Power On Self Test. The
computer will execute the POST action whenever you power on the computer. The POST
process is controlled by the BIOS. It is used to detect the status of the computer's main
components and peripherals. Each POST Code corresponds to different checkpoints that are
also defined by the BIOS in advance. For example, "memory presence test" is an important
checkpoint and its POST Code is "C1". When the BIOS execute any POST item, it will write the
corresponding POST Code into the address 80h. If the POST passes, the BIOS will process the
next POST item and write the next POST Code into the address 80h. If the POST fails, we can
check the POST Code in address 80h to find out where the problem lies.
See Appendix for AWARD POST Code definitions.
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