Appendix C Post Codes - Multitech CommPlete RAS96 User Manual

RAS96 RASCard User Guide

Appendix C POST Codes

EISA power-on self-test (POST) codes are typically output to port address 300h. ISA
POST codes are output to port address 80h.
Code
C0
1
2
3
4
5
6
7
BE
C1
C5
C6
8
9
A
B
C
D
E
70
Name Description
Turn Off Initialize standard devices with default values.
Processor Test 1 Processor Status (1FLAGS) Verification. Tests the following
processor status flags carry, zero, sign, and overflow. The
BIOS will set each of these flags, verify that they are set,
then turn each flag off and verify that it is off.
Processor Test 2 Read/Write/Verify with data patterns FF and 00 all CPU
registers except SS, SP, and BP.
Initialize Chips Disable NMI, PIE, AIE, UEI, SQWV. Disable video, parity
checking, and DMA. Reset math coprocessor. Clear all
page registers, CMOS shutdown byte. Initialize timers 0, 1,
and 2, and set EISA timer to a known state. Initialize DMA
controllers 0 and 1. Initialize interrupt controllers 0 and 1.
Initialize EISA extended registers.
Test Memory Refresh RAM must be periodically refreshed to keep the memory
Toggle from decaying. This function assures that the memory
refresh function is working properly.
Blank Video, Initialize Keyboard controller initialization.
Keyboard
Reserved
Test CMOS Interface Verifies CMOS is working correctly, detects a bad battery.
and Battery Status
Chipset Default Program chipset registers with power-on BIOS defaults.
Initialization
Memory Presence Test OEM-specific. Test to size on-board memory.
Early Shadow OEM-specific. Early Shadow enable for fast boot.
Cache Presence External cache size detection test
Setup Low Memory Early chipset initialization, memory presence test, OEM
chipset routines, clear low 64K of memory, test first 64K of
memory.
Early Cache Cache initialization.
Initialization
Setup Interrupt Vector Initialize first 120 interrupt vectors with
Table SPURIOUS_INT_HDLR and initialize INT 00h-1Fh
according to INT_TBL
Test CMOS RAM Test CMOS RAM checksum; if bad, or if insert key pressed,
Checksum load defaults. Verify real time clock.
Initialize keyboard Detect type of keyboard controller (optional). Set
NUM_LOCK status.
Initialize Video Interface Detect CPU clock. Read CMOS location 14h to detect type
of video in use. Detect and initialize video adapter.
Test Video Memory Test video memory, write sign-on message to screen. Set
up shadow RAM. Enable shadow according to Setup.
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