Micronics C400 System Board Manual
Appendix B: POST Codes
67
Appendix
B
POST Codes
The following tables list the Power On Self Test (POST)
codes, names and solutions. EISA POST codes are typically
output to port address 300h. ISA POST codes are output
to port address 80h.
Code
(hex)
Name Description
C0 Turn Off Chipset Cache OEM Specific-Cache control
1 Processor Test 1 Verification Processor Status (1FLAGS) Tests the following
processor status flags: carry, zero, sign, overflow, The
BIOS sets each flag, verifies they are set, then turns
each flag off and verifies it is off.
2 Processor Test 2 Read/Write/Verify all CPU registers except SS, SP, and
BP with data pattern FF and 00.
3 Initialize Chips 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.
4 Test Memory Refresh Toggle RAM must be periodically refreshed to keep the
memory from decaying. This function ensures that the
memory refresh function is working properly.
5 Blank video, Initialize keyboard Keyboard controller initialization.
6Reserved
7 Test CMOS Interface and Battery
Status
Verifies CMOS is working correctly,
BE Chipset Default Initialization Program chipset registers with power on BIOS defaults.
C1 Memory presence Test OEM Specific-Test to size on-board memory
C5 Early Shadow OEM Specific-Early Shadow enable for fast boot.
C6 Cache presence test External cache size detection
8 Setup low memory Early chip set initialization. Memory presence test.
OEM chip set routines. Clear low 64K of memory. Test
first 64K memory.
9 Early Cache Initialization Cyrix CPU initialization Cache initialization
A Setup Interrupt Vector Table Initialize first 120 interrupt vectors with
SPURIOUS_INT_HDLR and initialize INT 00h-1Fh
according to INT_TBL
B Test CMOS RAM Checksum Test CMOS RAM Checksum, if bad, or insert key
pressed, load defaults.
C Initialize Keyboard Detect type of keyboard controller (optional)x Set
NUM_LOCK status.
D Initialize Video Interface Detect CPU clock. Read CMOS location 14h to find out
type of video in use. Detect and Initialize Video
Adapter.
E Test Video Memory Test video memory, write sign-on message to screen.
Setup shadow RAM - Enable shadow according to
Setup.
F Test DMA BIOS checksum test. Controller 0 Keyboard detect and
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