User`s guide

C-14
User’s Guide
IA–32
POST Codes
Meaning
0x0008 Check CMOS diagnostic byte to determine if battery power is OK and set
error flags if necessary.
Verify CMOS checksum manually by reading storage area, if not O.K. load
with power–on default values and clear password.
Clear CMOS pending interrupt. Initialize Status Registers A in CMOS.
Next, checkpoint 0x0007.
0x0007 Initialize the BIOS update data area (BUP), and update the communication
vector between BIOS and INT13.
Initialize RT_CMOS_BYTE. INITIALIZES INT13 interrupt service routine to
just return. Next, checkpoint 0x000B.
0x000B Perform any necessary initialization before the keyboard controller BAT
command test. Next, checkpoint 0x000C.
0x000C The keyboard controller input buffer is free.
Next, issue BAT command and read result.
If bad 8042 then HALT! Next, checkpoint 0x000Eh.
0x000E The keyboard controller BAT command result has been verified.
Next, perform any necessary initialization after the keyboard controller BAT
command test. Next, checkpoint 0x000F.
0x000F Enable keyboard controller command byte, enable mouse if supported.
Next, checkpoint 0x0011
0x0011 Check if <Ins>, <Del>, or <End> key has been pressed, get POST informa-
tion.
Destroy CMOS checksum and set CMOS checksum error bit if indicated by
POST information.
Next, checkpoint 0x0012.
0x0012 Initialize CMOS and checksum with default values if END is pressed,
“Initialize CMOS in every boot” flag is set, or OEM method flag is set.
Disable #1 & #2 DMA controllers, disable #1 & #2 interrupt controllers, reset
video display EGA and monochrome devices.
Next, checkpoint 0x0013.
0x0013 Program chipset registers using POST tables, save good/bad cache status
to CMOS. Check for <Del> or OEM alternate key to enter setup. The DEL
key is also checked in the majority of the checkpoints from checkpoint 13h
to checkpoint 85h.
Initialize the chipset.
Next, checkpoint 0x0014.
0x0014 8254 PIT timer test on channel 2. The checking for the <Del> key press be-
tween here and checkpoint 27h. Will determine if Setup is invoked at
checkpoint 0x0087 for legacy keyboards only.
USB keyboards are initialized than.
Next, checkpoint 0x0019.
0x0019 Initialize system timer and check refresh toggle. HALT! If refresh toggle er-
ror.
Next, checkpoint 0x001A.
0x001A Read and compare high/low timing for refresh toggle. If not within accept-
able limits, HALT! Clear parity status, if any.
Next, checkpoint 0x0023.