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E.4
POST CODES
NOTE
ISA POST codes are output to port address 80h.
POST
Name
(hex)
01
BOOT BLOCK
03
Initialize Chips
04
Test Memory Refresh Toggle
05
Blank Video, Initialize Keyboard
06
EPROM Checksum
07
Test CMOS Interface and
Battery Status
08
Program Chipset default
09
Early Cache Initialization
0A
Setup Interrupt Vector Table
Description
Boot Block in EMERGENCY : Clear Base Memory Area.
1.
Clear CMOS shutdown byte.
2.
Initialize EISA extended registers. (Not for us since we don't
have EISA bus.)
RAM must be periodically refreshed in order to keep the memory
from decaying.
1.
Clear CMOS reset status
byte.
2.
Early Keyboard
initialization.
1.
Test F000h segment shadow readable and writeable for
POST access correct.
If not, show POST FE and beep continuously...
2.
Autodetect Flash EPROM.
1.
Install the TEKNOR segment.
2.
Verifies CMOS is working correctly (walking bit test).
3.
Restore CMOS from Flash if option is enabled.
4.
Check for OVERRIDE KEY (INSERT key).
Program Chipset default (show POST BEh).
1.
Check for Intel's and/or Cyrix CPU.
2.
Early Cache Initialization when cache is separate from
chipset.
3.
Turn off Gate A20.
1.
Initialize first 120 interrupt vectors with
SPURIOUS_INT_HDLR and initialize int. 00h-1Fh according
to INT_TBL.
2.
Early Power Management Initialization.
E-5
BIOS Setup Error Codes
Boot Block in EMERGENCY:
Initialize Keyboard Controller.
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