E-2Service Guide
Table E-1 POST Checkpoint List
Checkpoint Description
23h • Detects whether keyboard u is depressed from system powered-on till POST or not. If
yes, set BIOS Setup parameter too default settings; or keep the original settings.
24h • Tests programmable interrupt controller (8259)
• Initializes system interrupt
30h • Enables system shadow RAM
34h • Memory sizing
5Ah • Changes SMBASE, copy SMI Handler.
•
56h • Issues 1st software SMI to communicate with PMU.
• Initializes the SMI environment.
3Fh • Enable/Disable USB function
3Ch • Initializes interrupt vectors
3Eh • Set fixed CMOS setting
4Ch • CPU clock checking
• Sets the DRAM timing in correspondent to the system speed
35h • Scans PCI Devices to Initialize the PCI buffer that used by BIOS.
4Eh • Isolations for PnP ISA Card
4Fh • Configurations for PnP ISA Card
• Initializes the PCI device according to ESCD data (if ESCD data is valid).
• Initialize the PCI Devices by BIOS
• Initialize the PCI VGA card
50h • Initializes video display
Note: If system has any display card, here it should be initialized via its I/O ROM or
corresponding initialization program.
Exh • VGA BIOS POST.
54h • Enables video shadow RAM
58h • Displays Acer (or OEM) logo (if necessary)
• Displays Acer copyright message (if necessary)
• Displays BIOS serial number
5Ch • Memory testing
5Eh • Assign PCMCIA resource, enable serial IRQ
60h • External Cache sizing
• Enables/disables L1/L2 cache according to the BIOS SETUP
64h • Tests keyboard interface
Note: The keyboard LEDs should flash once.