Configuration
CP308
Page 4 - 16
ID 1027-4487, Rev. 3.0
P R E L I M I N A R Y
4.3.13
LED Configuration Register (LCFG)
The LED Configuration Register holds a series of bits defining the onboard configuration for the
front panel General Purpose LEDs.
Regardless of the selected configuration, the General Purpose LEDs are used to signal a num-
ber of fatal onboard hardware errors, such as:
LED3:
Power good status not reached (red)
LED2:
Hardware reset active/not deactivated (red)
LED1:
uEFI BIOS boot failure (red)
LED0:
uEFI BIOS boot failure (red)
1)
In uEFI BIOS POST mode (default), the LEDs build a binary vector to display uEFI BIOS
POST code during the uEFI BIOS boot phase. In doing so, the higher 4-bit nibble of the 8-bit
uEFI BIOS POST code is displayed followed by the lower nibble followed by a pause. uEFI
BIOS POST code is displayed in general in green color.
LED3:
POST bit 3 and bit 7 (green)
LED2:
POST bit 2 and bit 6 (green)
LED1:
POST bit 1 and bit 5 (green)
LED0:
POST bit 0 and bit 4 (green)
For further information on reading the 8-Bit uEFI BIOS POST Code, refer to Chapter 2.3.1.2,
“General Purpose LEDs”.
2)
Configured for General Purpose Mode, the LEDs are dedicated to functions as follows:
LED3:
LED 3, controlled by HOST (red/green)
LED2:
LED 2, controlled by HOST (red/green)
LED1:
LED 1, controlled by HOST (red/green)
LED0:
LED 0, controlled by HOST (red/green)
Table 4-16: LED Configuration Register (LCFG)
REGISTER NAME
LED CONFIGURATION REGISTER (LCFG)
ADDRESS
0x290
BIT
NAME
DESCRIPTION
RESET
VALUE
ACCESS
7 - 4
Res.
Reserved
0000
R
3 - 0
LCON
General Purpose LED Configuration:
0000 = POST
1)
0001 = General Purpose Mode
2)
0010 - 1111 = Reserved
0000
R/W
