AT & T BIOS POST Codes
- 01 - CPU test
- 02 - System I/O port test
- 03 - ROM checksum test
- 05 - DMA page register test
- 06 - Timer 1 test
- 07 - Timer 2 test
- 08 - RAM refresh test
- 09 - 8/19 bit bus conversion check
- 0A - Interrupt controller 1 test
- 0B - Interrupt controller 2 test
- 0C - Keyboard controller test
- 0D - CMOS RAM/RTC test
- 0E - Battery power test
- 0F - CMOS RAM checksum test
- 10 - CPU protected mode
- 11 - Display configuration test
- 12 - Display controller test
- 13 - Primary display error
- 14 - Extended CMOS test
- 15 - AT bus reset
- 16 - Initialize chipset registers
- 17 - Check for extension ROM's
- 18 - Internal memory address test
- 19 - Remap memory
- 1A - Memory interleave mode test
- 1B - Remap shadow memory
- 60 - Floppy controller/dr1C - Setup MRAM
- 1D - Expanded memory test
- 1E - AT memory error
- 1F - Internal memory error
- 20 - Minimum POST tests complete
- 21 - DMA controller 1 test
- 22 - DMA controller 2 test
- 23 - Timer 0 test
- 24 - Initialize internal controllers
- 25 - Unexpected interrupt
- 26 - Expected interrupt
- 30 - Switch to protected mode
- 31 - Size AT bus memory or size external memory
- 32 - Address lines A16 to A23 test
- 33 - Internal memory test or conventional memory test
- 34 - AT bus memory test or external memory test
- 38 - Shadow ROM BIOS to RAM
- 39 - Shadow extension BIOS to RAM
- 40 - Enable/disable keyboard
- 41 - Keyboard clock and data test
- 42 - Keyboard reset
- 43 - Keyboard controller test
- 44 - A20 gate test
- 50 - Initialize interrupt table
- 51 - Enable timer interrupt live test
- 61 - Hard disk controller test
- 62 - Initialize floppy drives
- 63 - Initialize hard drives
- 70 - Real time clock test
- 71 - Set real time clock
- 72 - Test parallel interfaces
- 73 - Test serial interfaces
- 74 - Check external ROM's
- 75 - Numeric coprocessor test
- 76 - Enable keyboard and RTC interrupts (IRQ 9)
- F0 - Display system startup message
- F1 - Check for ROM at E000h
- F2 - Boot from floppy or hard disk
- F3 - Run setup program
- F4 - Run password program
- FC - DRAM type detection
- FD - CPU register test