BIOS POST Check Point List 4-35
BIO
S
Se
tu
p
1A
The memory refresh line is toggling. Checking the 15us on/off
time.
23
Reading the 8042 input port and disabling the MEGAKEY
Green PC feature. Making the BIOS code segment writable
and performing any necessary configuration before
initializing the interrupt vectors.
24
The configuration or setup required before interrupt vector
initialization has been completed. Interrupt vector
initialization is about to begin.
25
Interrupt vector initialization is done. Clearing the password
if the POSTDIAG switch is on.
27
Performing initialization before setting video mode.
28
Beginning monochrome mode and color mode settings.
2A
Bus initialization system, static, output devices will be done,
if present.
2B
Passing control to the video ROM to perform any required
configuration before the video ROM test.
2C
Looking for optional video ROM to transfer control.
2D
The video ROM has returned control to BIOS POST.
Performing any required processing after the video ROM had
control.
2E
Completed post-video ROM test processing. If the EGA/VGA
controller is not found, perform the display memory read/
write test.
2F
EGA/VGA not found. Begin the display memory R/W test.
30
Display memory R/W test passed. Look for retrace checking.
31
Display memory R/W test or retrace checking failed. Begin
alternate display retrace checking.
Code
Description
(Continued)