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MITSUBISHI ELECTRIC FC810 User Manual

Page 30

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MITSUBISHI ELECTRIC MOTHERBOARD DIVISION

PAGE 30 OF 45

The BIOS also issues Port 80h codes that can be displayed using a suitable diagnostic card. The
codes can be used to determine the failure.

('

02h

Verify Real Mode

03h

Disable Non-Maskable Interrupt (NMI)

04h

Get CPU type

06h

Initialise system hardware

08h

Initialise chipset with initial POST values

09h

Set IN POST flag

0Ah

Initialise CPU registers

0Bh

Enable CPU cache

0Ch

Initialise caches to initial POST values

0Eh

Initialise I/ O component

0Fh

Initialise the local bus IDE

10h

Initialise Power Management

11h

Load alternate registers with initial POST values

12h

Restore CPU control word during warm boot

13h

Initialise PCI Bus Mastering devices

14h

Initialise keyboard controller

16h

BIOS ROM checksum

17h

Initialise cache before memory autosize

18h

8254 timer initialisation

1Ah

8237 DMA controller initialisation

1Ch

Reset Programmable Interrupt Controller

20h

Test DRAM refresh

22h

Test 8742 Keyboard Controller

24h

Set ES segment register to 4 GB

26h

Enable A20 line

28h

Autosize DRAM

29h

Initialise POST Memory Manager

2Ah

Clear 512 KB base RAM

2Ch

RAM failure on address line

2Eh

RAM failure on data bits of low byte of memory bus

2Fh

Enable cache before system BIOS shadow

30h

RAM failure on data bits of high byte of memory bus

32h

Test CPU bus- clock frequency

33h

Initialise Phoenix Dispatch Manager

34h

Test CMOS RAM

35h

Initialise alternate chipset registers.