Post Codes - Teknor Industrial Computers TEK-AT4LVG Technical Reference Manual

18.07.4

POST Codes

Note: EISA POST codes are typically output to port address 300h.
ISA POST codes are output to port address 80h.
POST Name
(hex)
CO Turn Off Chipset Cache OEM Specific-Cache control
1 Processor Test 1
2 Processor Test 2
3 Initialize Chips
4 Test Memory Refresh
Toggle
5 Blank video,
Initialize keyboard
6 Reserved
7 Test CMOS Interface
and Battery Status
BE Chipset Default
Initialization
C1 Memory presence test
C5 Early Shadow
C6 Cache presence test
Appendices 18-22
Description
Processor Status (1FLAGS) Verification.
Tests the following processor status flags: Carry,
zero, sign, overflow.
The BIOS will set each of these flags, verify they
are set, then turn each flag off and verify it is off.
Read/Write/Verify all CPU registers except SS, SP,
and BP with data pattern FF and 00.
Disable NMI, PIE, AIE, UEI, SQWV.
Disable video, parity checking, DMA.
Reset math coprocessor.
Clear all page registers, CMOS shutdown byte.
Initialize timer 0, 1, and 2, including set EISA
timer to a known state.
Initialize DMA controllers 0 and 1.
Initialize interrupt controllers 0 and 1.
Initialize EISA extended registers.
RAM must be periodically refreshed in order to
keep the memory from decaying. This function
assures that the memory refresh function is
working properly.
Keyboard controller initialization.
Verifies CMOS is working correctly, detects bad
battery.
Program chipset registers with power on BIOS
defaults.
OEM Specific-Test to size on-board memory.
OEM Specific-Early Shadow enable for fast boot.
External cache size detection.