Chassis Plans ATXP-875P, Technical Reference

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Appendix B: Flash Bios ATXP-875P – Technical Reference
66 Chassis Plans
Table B-3 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 checkpoints that may occur during the POST portion of the BIOS:
Checkpoint
Code
Description
03 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."
04 Check CMOS diagnostic byte to determine if battery power is OK and
CMOS checksum is OK. Verify CMOS checksum manually by reading
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
05 Initializes the interrupt controlling hardware (generally PIC) and interrupt
vector table.
06 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
interrupt.
Traps INT1Ch vector to "POSTINT1ChHandlerBlock."
C0 Early CPU Init Start -- Disable Cache - Init Local APIC
C1 Set up boot strap processor Information
C2 Set up boot strap processor for POST
C5 Enumerate and set up application processors
C6 Re-enable cache for boot strap processor
C7 Early CPU Init Exit
0A Initializes the 8042 compatible Key Board Controller.
0B Detects the presence of PS/2 mouse.
0C Detects the presence of Keyboard in KBC port.
0E 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.
13 Early POST initialization of chipset registers.
24 Uncompress and initialize any platform specific BIOS modules.
30 Initialize System Management Interrupt.
2A Initializes different devices through DIM.
See
DIM Code Checkpoints section of document for more information.
2C Initializes different devices. Detects and initializes the video adapter
installed in the system that have optional ROMs.
2E Initializes all the output devices.
31 Allocate memory for ADM module and uncompress it. Give control to
ADM module for initialization. Initialize language and font modules for
ADM. Activate ADM module.
33 Initializes the silent boot module. Set the window for displaying text
information.
37 Displaying sign-on message, CPU information, setup key message, and
any OEM specific information.
38 Initializes different devices through DIM. See DIM Code Checkpoints
section of document for more information.
39 Initializes DMAC-1 & DMAC-2.