GL815E Endura Motherboard Product Manual
Page 34 of 51
4.4 BIOS Error Indications
Once the motherboard powers-up the BIOS code runs Power-On-Self-Test software to check that
the motherboard is operating correctly. During this process, the code writes an 8-bit value to an
error port at various code checkpoints. If a fatal error is determined, then the error code indicates
the last successful checkpoint reached. The BIOS will attempt to write this code to the display. The
error port (I/O location 80h) can be read via “off-the-shelf” Debug cards. The table below lists the
checkpoint codes.
There are a number of checkpoints that also generate an audible ‘beep’ code on failure using the
standard PC speaker (also routed though the motherboard audio system). The beep codes are
made up of up to 4 groups of short beeps and are also listed below.
Once the video is enabled further errors generated during and after POST are sent to the video
display as text messages. These messages are always displayed unless the motherboard is
configured for silent boot or headless (no keyboard, mouse or display) operation.
BIOS POST Checkpoint Codes
02h Verify Real Mode 6Ch Display shadow message
03h Disable NMI 6Eh Display non-disposable segments
04h Get CPU type 70h Display error messages
06h Initialize system hardware 72h Check for configuration errors
08h
Initialize chipset registers with initial
POST values
74h Test real-time clock
09h Set in POST flag 76h Check for keyboard errors
0Ah Initialize CPU registers 7Ah Test for key lock on
0Bh Enable CPU cache 7Ch Set up hardware interrupts vectors
0Ch Initialize cache to initial POST values 7Eh Test coprocessor if present
0Eh Initialize I/O 80h Disable onboard I/O ports
0Fh Initialize local bus IDE 8"h Late device initialization
"0h Initialize Power Management 82h Detect and install external RS232 ports
""h Load alternate registers with initial
POST values
83h Configure IDE controller
"2h Restore CR0 84h Detect and install external parallel ports
"3h Reset PCI BM 85h Initialize PCI PCC devices
"4h Initialize keyboard controller 86h Re-initialize onboard I/O ports
"6h BIOS ROM checksum 87h Configure MCD devices
"7h Pre-size DRAM 88h Initialize BIOS Data Area
"8h 8254 timer initialization 89h Enable NMI
"Ah 8237 DMA controller initialization 8Ah Initialize Extended BIOS Data Area
"Ch
Reset Programmable Interrupt
Controller
8Bh Initialize mouse
20h Test DRAM refresh 8Ch Initialize floppy controller
22h Test 8742 Keyboard Controller 8Eh Execute auto-typing
24h Set ES segment to register to 4GB 8Fh Hard disk controller fast pre-initialization
