MSI IB-945GC User Manual

Page 53

4-3

MS-9868

POST Code Checkpoints

The POST code checkpoints are the largest set of checkpoints during the

BIOS pre-boot process. The following table describes the type of check-

points that may occur during the POST portion of the BIOS:

Checkpoint

Description

Disable NMI, Parity, video for EGA, and DMA controllers. Initialize

BIOS, POST, Runtime data area. Also initialize BIOS modules on

POST entry and GPNV area. Initialized CMOS as mentioned in the

Kernel Variable “wCMOSFlags.”

Check CMOS diagnostic byte to determine if battery power is OK and

CMOS checksum is OK. Verify CMOS checksum manually by read-

ing 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

Initializes the interrupt controlling hardware (generally PIC) and inter-

rupt vector table.

Do R/W test to CH-2 count reg. Initialize CH-0 as system timer. Install

the POSTINT1Ch handler. Enable IRQ-0 in PIC for system timer inter-

rupt. Traps INT1Ch vector to “POSTINT1ChHandlerBlock.”

Initializes the CPU. The BAT test is being done on KBC. Program the

keyboard controller command byte is being done after Auto detection

of KB/MS using AMI KB-5.

Initializes the 8042 compatible Key Board Controller.

Detects the presence of PS/2 mouse.

Detects the presence of Keyboard in KBC port.

Testing and initialization of different Input Devices. Also, update the

Kernel Variables. Traps the INT09h vector, so that the POST INT09h

handler gets control for IRQ1. Uncompress all available language,

BIOS logo, and Silent logo modules.