NCR AT BIOS Post Codes
- 01 - Test the CPU registers
- 02 - Test system support I/O
- 03 - Test BIOS ROM checksum
- 04 - Test DMA page registers
- 05 - Test timer channel 1
- 06 - Test timer channel 2
- 07 - Test RAM refresh logic
- 08 - Test base 64KB
- 09 - Test 8/16 bit bus conversion
- 0A - Test interrupt controller 1
- 0B - Test interrupt controller 2
- 0C - Test I/O controller
- 0D - Test CMOS RAM read/write operation
- 0E - Test battery power
- 0F - Test CMOS RAM checksum
- 10 - Test CPU protected mode
- 11 - Test video configuration
- 12 - Test primary video controller
- 13 - Test secondary video controller
- 20 - Display results of tests to this point
- 21 - Test DMA controller 1
- 22 - Test DMA controller 2
- 23 - Test system timer channel 0
- 24 - Initialize interrupt controllers
- 25 - Test interrupts
- 26 - Test interrupts
- 30 - Check base 640KB memory
- 31 - Check extended memory size
- 32 - Test higher 8 address lines
- 33 - Test base memory
- 34 - Test extended memory
- 40 - Test keyboard
- 41 - Test keyboard
- 42 - Test keyboard
- 43 - Test keyboard
- 44 - Test A20 gate
- 50 - Setup hardware interrupt vectors
- 51 - Enable interrupt timer channel 0
- 52 - Check BIOS ROM
- 60 - Test floppy disk controller and drive
- 61 - Test hard disk controller
- 62 - Initialize floppy drives
- 63 - Initialize hard drives
- 70 - Test real time clock
- 71 - Set time of day in RTC
- 72 - Check parallel interface ports
- 73 - Check serial interface ports
- 74 - Check for any option ROM's
- 75 - Check math coprocessor
- 76 - Enable keyboard and RTC interrupts
- F0 - System not configured properly or hardware defect
- F1 - Scan and execute any option ROM's
- F2 - Call interrupt 19 boot loader