HP e-Vectra Technical Information download pdf (Page 46)

BIOS Overview

Checkpoint

Code

POST Routine Description

D6 Control is in segment 0. To check

key and verify main BIOS checksum. If either

is pressed or main BIOS checksum is bad, go to check point E0 else go to check point D7.

D7 To pass control to Interface Module.

D8 Main BIOS runtime code is to be decompressed.

D9 Control to be passed to main BIOS in shadow RAM. Boot Block Recovery Code Check Points.

E0 OnBoard Floppy Controller (if any) is initialized. To start base 512K memory test.

E1 To initialize interrupt vector table.

E2 To initialize DMA and interrupt controllers.

E6 To enable floppy and timer IRQ, enable internal cache.

ED Initialize floppy drive.

EE Start looking for a diskette in drive A: and read 1st sector of the diskette.

EF Floppy read error.

F0 Start searching '

AMIBOOT.ROM

' file in root directory.

F1 '

AMIBOOT.ROM

' file not present in root directory.

F2 Start reading FAT table and analyze FAT to find the clusters occupied by '

AMIBOOT.ROM

' file.

F3 Start reading '

AMIBOOT.ROM

' file cluster by cluster.

F4 '

AMIBOOT.ROM

' file not of proper size.

F5 Disable internal cache.

FB Detect Flash type present.

FC Erase Flash.

FD Program Flash.

FF Flash program successful. BIOS is going to restart. Runtime code is uncompressed in F000 shadow ram.

03 NMI is Disabled. To check soft reset/power-on.

05 BIOS stack set. Going to disable Cache if any.

06 POST code to be uncompressed.

07 CPU init and CPU data area init to be done.

08 CMOS checksum calculation to be done next.

0B Any initialization before keyboard BAT to be done next.

0C KB controller I/B free. To issue the BAT command to keyboard controller.

0E Any initialization after KB controller BAT to be done next.

0F Keyboard command byte to be written.

10 Going to issue Pin-23,24 blocking/unblocking command.

11 Going to check pressing of

<INS>

<END>

key during power-on.

12 To init CMOS if "Init CMOS in every boot" is set or

<END>

key is pressed. Going to disable DMA and Interrupt

controllers.

13 Video display is disabled and port-B is initialized. Chipset init about to begin.

14 8254 timer test about to start.

19 About to start memory refresh test.

1A Memory Refresh line is toggling. Going to check 15us ON/OFF time.

23 To read 8042 input port and disable Megakey GreenPC feature. Make BIOS code segment writeable.

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HP e-Vectra Technical Information Page 46

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