NCR BIOS Post Codes - BIOS Central

NCR PC6 (XT) BIOS Post Codes
NCR AT BIOS Post Codes
NCR PC916 BIOS Post Codes

NCR PC6 (XT) BIOS Post Codes:

AA	8088 CPU failure
B1	2764 EPROM checksum failure
B2	8237 DMA controller failure
B3	8253 PIT failure
B4	RAM failure
B5	8259 PIC failure
B6	RAM parity failure
BB	All tests passed, ready to boot

Return to Top

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

Return to Top

NCR PC916 BIOS Post Codes:

01	Test CPU registers
03	Test BIOS ROM checksum
04	Test DMA page registers
05	Test timer channel 1
06	Test timer channel 2
0C	Test 8042 keyboard controller
14	Test disabling speed stretch at port 69h
15	Start refresh timer 1
16	Enable speed stretch at port 69h
17	Clear write protect bit
1B	Test 64KB shadow RAM
18	Write and test interrupt descriptor table
19	Verify RAM
02	Verify port 61h
07	Test refresh logic
08	Test base 64KB RAM
09	Test 8/16 bit bus conversion logic
0A	Test interrupt mask register A
0B	Test interrupt mask register B
1A	Check 8042 keyboard controller
0D	Test CMOS RAM shutdown byte
0E	Test CMOS RAM battery power
0F	Test CMOS RAM checksum
10	Test CPU protected mode
11	Test video configuration
12	Initialize and test primary video controller
13	Primary video error
20	Display results of tests to this point
21	Test DMA controller 1
22	Test DMA controller 2
23	Test timer 1 counter 0 840nS clock timer
27	Test timer 2 counter 0 for NMI
28	Test timer 2 counter
24	Initialize both interrupt controllers
25	Check for unexpected interrupts
26	Wait for interrupt
30	Check base 640KB memory
31	Check extended memory size
32	Test higher 8 address lines
33	Test base memory
34	Test extended memory up to 256MB
35	Test RAM in segment E000h
40	Test keyboard enable/disable
41	Test keyboard reset command
42	Test keyboard
43	Test keyboard
F4	Display speed setting
45	Initialize the mouse and enable IRQ 1
44	Test address overrun capability
50	Set up hardware interrupt vectors
51	Enable IRQ 0 interval interrupt from timer 0
60	Test for floppy and hard disk controllers and drives
61	Test disk controller
62	Initialize floppy drives
63	Initialize hard drives
74	Check and execute option ROM's from C8000h to DFFFFh
70	Test RTC
71	Set interval timer
72	Configure and test parallel interface
73	Configure and test serial interface
75	Test math coprocessor if installed
76	Enable keyboard and RTC
F0	Display and logged errors
F6	Test base memory
F3	Got to setup if F1 was pressed
F4	Display speed setting
F5	Initialize counter 2 for speed testing
F1	Test system code at E0000h and copy video ROM to shadow memory
F2	Call interrupt 19 boot loader
F6	Test base memory
F7	Test extended memory

Return to Top

All information has been gathered with permission of the respective BIOS providers. Although Bios Central has used reasonable effort to ensure accuracy we are unable to verify all codes posted. Use at your own risk. Bios Central, or any person associated with Bios Central takes no responsibility for any dmage resulting from the use of this information.