Bull NovaScale T840, User Manual, Page: 256 / 302

User Guide
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Diagnostic LEDs
During the system boot process, BIOS executes several platform configuration
processes, each of which is assigned a specific hex POST code number. As each
configuration routine is started, the BIOS will display the POST code on the POST
code diagnostic LEDs found on the back edge of the server board. 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 is represented by a combination of colors from the four LEDs. The
LEDs are capable of displaying three colors: green, red, and amber.
Table 17: POST Progress Code LED Example
8h 4h 2h 1h
LEDs Red Green Red Green Red Green Red Green
ACh 1 1 0 1 1 0 0 0
Result Amber Green Red Off
MSB LSB
Table 18: Diagnostic LEDs Codes
Check Point Diagnostic LED
Decoder
(G=green; R=red; A=amber)
Description
MSB LSB
Host Processor
0x10h OFF OFF OFF R Power-on initialization of the host processor (bootstrap
processor)
Host Processor
0x11h OFF OFF OFF A Host processor cache initialization
0x12h OFF OFF G R Starting application processor initialization
0x13h OFF OFF G A SMM initialization
Chipset
0x21h OFF OFF R G Initializing a chipset component
Memory
0x22h OFF OFF A OFF
0x23h OFF OFF A G
0x24h OFF G R OFF
0x25h OFF G R G
0x26h OFF G A OFF