AMI (AMERICAN MEGATRENDS INC.)
CHECK POINT CODES FOR PRE 4/9/90 BIOS
The 286 and later AMI bios's have a check point trace in them to
indicate where the code is at should a problem occur while booting.
This checkpoint code is output to port 80 as a hex code and can be
monitored with a special board costing about 50$ available in several
magazine adds. The following is a list of the codes for pre 4/9/90
286 bios's.
01____NMI is disabled, and 286 registor test about to start
02____286 registor test is finished
03____ROM checksum OK (F000:0000--->F000:FFFF)
04____8259 initialization OK
05____CMOS pending interrupt disabled
06____Video disabled and system timer counting OK
07____channel 2 of 8253 test OK
08____channel 2 delta count test OK
09____channel 1 delta count test OK
0A____channel 0 delta count test OK
0B____parity status cleared
0C____refresh and system timer OK
0D____refresh link toggling OK
0E____refresh periods on/off 50% OK
0F____??????
10____confirmed that refresh is on and about to start 64k memory
11____address line test OK
12____64k base memory test OK
13____interrupt vectors initialized
14____8042 keyboard controller test OK
15____CMOS read/write test is OK
16____CMOS checksum/battery check is OK
17____monochrome mode set OK
18____color mode set OK
19____start to look for optional video ROM
1A____optional video ROM control OK
1B____display memory read/write test OK
1C____display memory read/write test for alternate display is OK
1D____video retrace check is OK
1E____global equipment byte set for video OK
1F____mode set call for mono/color OK
20____video test is OK
21____video display OK
22____power on message display is OK
23---->2F ???????
30____virtual mode memory test about to start
31____virtual mode memory test started
32____processor in virtual mode
33____memory address line test in progress
34____memory address line test in progress
35____memory below 1MB calculated
36____memory size computed OK
37____memory test in progress
38____memory initialization finished below 1MB
39____memory initialization finished above 1MB
3A____display the memory size
3B____about to start memory test below 1MB
3C____memory test below 1MB OK
3D____memory test over 1MB OK
3E____about to go to real mode (shutdown)
3F____shutdown was successful and entered real mode OK
40____attempt disable A20 address ling
41____gate A20 line disabled successfully
42____about to start DMA controller test
43---->4d ????
4E____address line test OK
4F____processor in real mode after shutdown
50____DMA page registor test OK
51____DMA unit 1 base registor test about to start
52____DMA unit 1 channel OK, about to start channel 2
53____DMA channel 2 base registor test OK
54____about to test f/f latch for unit 1
55____f/f latch test both units OK
56____DMA unit 1 and 2 programmed OK
57____8259 initialization over
58____8259 mask registor check OK
59____master 8259 mask registor OK and about to start slave
5A____about to check timer and keyboard interrupt level
5B____timmer interrupt OK
5C____about to test keyboard interrupt
5D____ERROR! timer/keyboard interrupt not in proper level
5E____8259 interrupt controller error
5F____8259 interrupt controller test OK
60---->6F ????
70____start of keyboard test
71____keyboard BAT test OK
72____keyboard test OK
73____keyboard global data initialization OK
74____floppy setup about to start
75____floppy setup OK
76____hard disk setup about to start
77____hard disk setup OK
78____
79____about to initialize timer data area
7A____verify CMOS battery power
7B____CMOS battery verify OK
7C____
7D____about to analyze diagnostic test results for memory
