Справочник Пользователя для Acer Altos R520

 5 Troubleshooting

142

Diagnostic POST code LEDs

During the system boot process, BIOS executes a number of platform 
configuration processes, each of which is assigned a specific hex code 
number. As each configuration routine is started, BIOS will display the 
given POST code to the diagnostic POST code LEDs found on the rear of 
the mainboard. To assist in troubleshooting a system hang during the 
POST process, the diagnostic LEDs can be used to identify the last POST 
process to be executed. 

Each POST code will be represented by a combination of colors from 
the four LEDs. The LEDs are capable of displaying three colors: green, 
red, and amber. Each bit in the upper nibble is represented by a red 
LED and each bit in the lower nibble is represented by a green LED. If 
both bits are set in the upper and lower nibbles then both red and 
green LEDs are lit, resulting in an amber color. If both bits are clear, 
then the LED is off.

Diagnostic LED placement diagram

The following table lists the possible POST codes that may be displayed 
on the Diagnostic POST code LEDs during system initialization.  

0x10h

OFF

OFF

OFF

R

Power-on initialization of the host 
processor (bootstrap processor)

0x11h

OFF

OFF

OFF

A

Host processor cache initialization 
(including AP)

0x12h

OFF

OFF

G

R

Starting application processor 
initialization

 

Back edge of server board

 

 

 

Diagnostic LEDs