BOXD865PERL Intel, BOXD865PERL Datasheet - Page 129

• Manufacturer Part Number: BOXD865PERL
• Manufacturer: Intel

Specifications of BOXD865PERL

• Lead Free Status / Rohs Status: Supplier Unconfirmed

5.3 Bus Initialization Checkpoints
Table 82.
The system BIOS gives control to the different buses at several checkpoints to do various tasks.
Table 83 describes the bus initialization checkpoints.
Table 83.
While control is inside the different bus routines, additional checkpoints are output to port 80h as
WORD to identify the routines under execution. In these WORD checkpoints, the low byte of the
checkpoint is the system BIOS checkpoint from which the control is passed to the different bus
routines. The high byte of the checkpoint is the indication of which routine is being executed in
the different buses. Table 84 describes the upper nibble of the high byte and indicates the function
that is being executed.
Table 84.
Value
0
1
2
3
4
5
6
7
Code
AE
B1
00
Checkpoint
2A
38
39
95
Description of POST Operation
Uncompress SMBIOS module and init SMBIOS code and form the runtime SMBIOS image in
shadow.
Going to copy any code to specific area.
Copying of code to specific area done. Going to give control to INT-19 boot loader.
Runtime Code Uncompressed in F000 Shadow RAM (continued)
Bus Initialization Checkpoints
Upper Nibble High Byte Functions
Description
func#0, disable all devices on the bus concerned.
func#1, static devices init on the bus concerned.
func#2, output device init on the bus concerned.
func#3, input device init on the bus concerned.
func#4, IPL device init on the bus concerned.
func#5, general device init on the bus concerned.
func#6, error reporting for the bus concerned.
func#7, add-on ROM init for all buses.
Different buses init (input, IPL, and general devices) to start if present.
Display different buses initialization error messages.
Init of different buses optional ROMs from C800 to start.
Description
Different buses init (system, static, and output devices) to start if present.
Error Messages and Beep Codes
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