D R A F T — F O R I N
T E R N A L U S E O N L Y
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User Guide
CP3010-SA
2.7.1.2 General Purpose LEDs
The General Purpose LEDs (LED3..0) are designed to indicate the boot-up POST code after which they
are available to the application. If the LED3..0 are lit red during boot-up, a failure is indicated. In this
event, please contact Kontron for further assistance.
The POST code is indicated during the boot-up phase. After boot-up, the LEDs indicate General Purpose
or Port 80 signals, depending on the uEFI BIOS settings. The default setting after boot-up is General
Purpose.
For further information regarding the configuration of the General Purpose LEDs, refer to Chapter
3.3.7, LED Configuration Register, and Chapter 3.3.8, LED Control Register.
Note:
The bit allocation for Port 80 is the same as for the POST code.
How to Read the 8-Bit POST Code
Due to the fact that only 4 LEDs are available and 8 bits must be displayed, the POST code output is
multiplexed on the General Purpose LEDs.
Table 8: General Purpose LEDs Function
LED
COLOR
FUNCTION
DURING BOOT-UP
FUNCTION DURING uEFI BIOS POST
(if POST code config. is enabled)
FUNCTION
AFTER BOOT-UP
LED3 red
Power
failure
--
General Purpose or Port 80
Default: General Purpose
green
--
uEFI BIOS POST bit 3 and bit 7
red+green
--
--
LED2
red
CPU catastrophic error
CPU catastrophic error
General Purpose or Port 80
Default: General Purpose
green
--
uEFI BIOS POST bit 2 and bit 6
red+green
--
--
LED1
red
Hardware reset
--
General Purpose or Port 80
Default: General Purpose
green
--
uEFI BIOS POST bit 1 and bit 5
red+green
--
--
LED0
red
uEFI BIOS boot failure
--
General Purpose or Port 80
Default: General Purpose
green
--
uEFI BIOS POST bit 0 and bit 4
red+green
--
--
Table 9: POST Code
Sequence
STATE
GENERAL PURPOSE LEDs
0
All LEDs are OFF; start of POST sequence
1
High nibble
2
Low nibble; state 2 is followed by state 0
