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Configuration
4.4.14
LED Configuration Register (LCFG)
The LED Configuration Register holds a series of bits defining the onboard configuration of the
General Purpose LEDs (LED 0..3). For the location of the General Purpose LEDs, refer to
Figure 1-6.
Table 4-20: LED Configuration Register (LCFG)
REGISTER NAME
ADDRESS
BIT
NAME
7-4
Res.
Reserved
3-0
LCON
LED Configuration:
0000 = POST
0001 = Mode A
0010 - 1111 = Reserved
1)
In uEFI BIOS POST mode, the General Purpose LEDs build a binary vector to display uEFI
BIOS POST code during the pre-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. The 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)
2)
Configured for Mode A, the General Purpose LEDs are dedicated to functions as follows:
LED3:
LED 3 (red/green/red+green)
LED2:
LED 2 (red/green/red+green)
LED1:
LED 1 (red/green/red+green)
LED0:
LED 0 (red/green/red+green)
Besides the configurable functions described above, the General Purpose LEDs fulfill also a
basic debug function during the power-up phase as long as the first access to Port 80 is pro-
cessed. If an LED lights red and stays red, than a basic error is present on the board. The fol-
lowing debug functions are defined and displayed during this initialization phase.
LED3:
PGOOD, Power Good status not reached (red)
LED2:
CPU catastrophic error (red)
LED1:
RST, PCI reset active / not deactivated (red)
LED0:
uEFI BIOS boot failure (red)
Page 4 - 18
LED CONFIGURATION REGISTER (LCFG)
DESCRIPTION
1)
2)
0x290
ID 1044-9757, Rev. 2.0
CP6003-SA
RESET
ACCESS
VALUE
0000
R
0001
R/W
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