BIOS Quick Reference • CC5-RAVE
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EKF Elektronik GmbH * Philipp-Reis-Str. 4 * D-59065 HAMM (Germany)
Tel. +49 (0)2381/6890-0 * Fax. +49 (0)2381/6890-90 * E-Mail [email protected] * Internet http://www.ekf.de
Addendum A: Embedded BIOS POST Codes
Embedded BIOS writes progress codes, also known as POST codes, to I/O port 80H during POST,
in order to provide information to system integrators and developers about system faults. These
POST are not displayed on the screen. However, the POST codes can be displayed by means of
additional emulator equipment. For more information about POST codes, contact General
Software.
Mnemonic Code Code System Progress Report
POST_STATUS_START 00h Start POST (BIOS is executing).
POST_STATUS_CPUTEST 01h Start CPU register test.
POST_STATUS_DELAY 02h Start power-on delay.
POST_STATUS_DELAYDONE 03h Power-on delay finished.
POST_STATUS_KBDBATRDY 04h Keyboard BAT finished.
POST_STATUS_DISABSHADOW 05h Disable shadowing & cache.
POST_STATUS_CALCCKSUM 06h Compute ROM CRC, wait for KBC.
POST_STATUS_CKSUMGOOD 07h CRC okay, KBC ready.
POST_STATUS_BATVRFY 08h Verifying BAT command to KB.
POST_STATUS_KBDCMD 09h Start KBC command.
POST_STATUS_KBDDATA 0ah Start KBC data.
POST_STATUS_BLKUNBLK 0bh Start pin 23,24 blocking & unblocking.
POST_STATUS_KBDNOP 0ch Start KBC NOP command.
POST_STATUS_SHUTTEST 0dh Test CMOS RAM shutdown register.
POST_STATUS_CMOSDIAG 0eh Check CMOS checksum.
POST_STATUS_CMOSINIT 0fh Initialize CMOS contents.
POST_STATUS_CMOSSTATUS 10h Initialize CMOS status for date/time.
POST_STATUS_DISABDMAINT 11h Disable DMA, PICs.
POST_STATUS_DISABPORTB 12h Disable Port B, video display.
POST_STATUS_BOARD 13h Initialize board, start memory bank detection.
POST_STATUS_TESTTIMER 14h Start timer tests.
POST_STATUS_TESTTIMER2 15h Test 8254 T2, for speaker, port B.
POST_STATUS_TESTTIMER1 16h Test 8254 T1, for refresh.
POST_STATUS_TESTTIMER0 17h Test 8254 T0, for 18.2Hz.
POST_STATUS_MEMREFRESH 18h Start memory refresh.
POST_STATUS_TESTREFRESH 19h Test memory refresh.
POST_STATUS_TEST15US 1ah Test 15usec refresh ON/OFF time.
POST_STATUS_TEST64KB 1bh Test base 64KB memory.
POST_STATUS_TESTDATA 1ch Test data lines.
POST_STATUS_TESTADDR 20h Test address lines.
POST_STATUS_TESTPARITY 21h Test parity (toggling).
POST_STATUS_TESTMEMRDWR 22h Test Base 64KB memory.
POST_STATUS_SYSINIT 23h Prepare system for IVT initialization.
POST_STATUS_INITVECTORS 24h Initialize vector table.
POST_STATUS_8042TURBO 25h Read 8042 for turbo switch setting.
POST_STATUS_POSTTURBO 26h Initialize turbo data.
POST_STATUS_POSTVECTORS 27h Modification of IVT.
POST_STATUS_MONOMODE 28h Video in monochrome mode verified.
POST_STATUS_COLORMODE 29h Video in color mode verified.
POST_STATUS_TOGGLEPARITY 2ah Toggle parity before video ROM test.
POST_STATUS_INITBEFOREVIDEO 2bh Initialize before video ROM check.
POST_STATUS_VIDEOROM 2ch Passing control to video ROM.
POST_STATUS_POSTVIDEO 2dh Control returned from video ROM.
POST_STATUS_CHECKEGAVGA 2eh Check for EGA/VGA adapter.
POST_STATUS_TESTVIDEOMEMORY 2fh No EGA/VGA found, test video memory.
POST_STATUS_RETRACE 30h Scan for video retrace signal.
POST_STATUS_ALTDISPLAY 31h Primary retrace failed.
POST_STATUS_ALTRETRACE 32h Alternate found.
POST_STATUS_VRFYSWADAPTER 33h Verify video switches.
POST_STATUS_SETDISPMODE 34h Establish display mode.
POST_STATUS_CHECKSEG40A 35h Initialize ROM BIOS data area.
POST_STATUS_SETCURSOR 36h Set cursor for power-on msg.
POST_STATUS_PWRONDISPLAY 37h Display power-on message.
POST_STATUS_SAVECURSOR 38h Save cursor position.
POST_STATUS_BIOSIDENT 39h Display BIOS identification string.
