Acer G520 series manual Post Code Checkpoints, Msblsb OFF

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POST Code Checkpoints

Each of the four LEDs can have one of four states: Off, Green, Red, or Amber. The LED diagnostics feature consists of a hardware decoder and four dual color LEDs. During POST, the LEDs will display all normal Port80 codes representing the progress of the BIOS POST. Each postcode will be represented by a combination of colors from the 4 LEDs. During the POST process, each light sequence represents a specific Port-80 POST code. If a system should hang during POST, the Diagnostic LEDs will present the last test executed before the hang. When reading the lights, the LEDs should be observed from the back of the system.

Diagnostic LED Decoder

Check

point

G=Green, R=Red, A+Amber Description

MSBLSB

03	OFF	OFF	G	G	Disable NMI, parity, video
					for EGA, and 03DMA
					controllers. Initialize BIOS,
					POST, Run-time data area.
					Initialize BIOS modules on
					POST entry and GPNV
					area. Initialized CMOS as
					mentioned in the Kernel
					Variable “wCMOSFlags”
04	OFF	G	OFF	OFF	Check CMOS diagnostic
					byte to determine if

battery power is OK and CMOS checksum is OK. Verify CMOS checksum manually by reading storage area. If the CMOS checksum is bad, update CMOS with power-on default values and clear passwords. Initialize status register A.

Initializes data variables that are based on CMOS setup questions. Initializes both the 8259 compatible PICs in the system