Acer Altos R720 Series User Manual page 160

150
Diagnostic LED Decoder
Checkpoint
G=Green, R=Red, A=Amber
code
MSB
0x13h OFF
Chipset
0x21h OFF
Memory
0x22h OFF
0x23h OFF
0x24h OFF
0x25h OFF
0x26h OFF
0x27h OFF
0x28h G
PCI Bus
0x50h OFF
0x51h OFF
0x52h OFF
0x53h OFF
0x54h OFF
0x55h OFF
0x56h OFF
0x57h OFF
USB
0x58h G
0x59h G
LSB
OFF G A
OFF R G
OFF A OFF
OFF A G
G R OFF
G R G
G A OFF
G A G
OFF R OFF
R OFF R
R OFF A
R G R
R G A
A OFF R
A OFF A
A G R
A G A
R OFF R
R OFF A
5 Troubleshooting
Description
SMM initialization
Initializing a chipset component
Reading configuration data from
memory (SPD on DIMM)
Detecting presence of memory
Programming timing parameters in
the memory controller
Configuring memory parameters in
the memory controller
Optimizing memory controller
settings
Initializing memory, such as ECC init
Testing memory
Enumerating PCI busses
Allocating resources to PCI busses
Hot Plug PCI controller
initialization
Reserved for PCI bus
Reserved for PCI bus
Reserved for PCI bus
Reserved for PCI bus
Reserved for PCI bus
Resetting USB bus
Reserved for USB devices