AT Technical Information
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39
5.4. INTERRUPT MAP
NMI:
Parity check error
IRQ (H/W):
0 System TIMER interrupt from TIMER-0
1 KEYBOARD output buffer full
2 Cascade for IRQ 8-15
3 SERIAL port 2
4 SERIAL port 1
5 PARALLEL port 2
6 FLOPPY DISK adapter
7 PARALLEL port 1
8 RTC clock
9 Available
10 Available
11 Available
12 Available
13 MATH coprocessor
14 HARD DISK adapter
15 Available
5.5. RTC & CMOS RAM MAP
RTC & CMOS:
00
Seconds
01
Second alarm
02
Minutes
03
Minutes alarm
04
Hours
05
Hours alarm
06
Day of week
07
Day of month
08
Month
09
Year
0A
Status register A
0B
Status register B
0C
Status register C
0D
Status register D
0E
Diagnostic status byte
0F
Shutdown byte
10
FLOPPY DISK drive type byte
11
Reserve
12
HARD DISK type byte
13
Reserve
14
Equipment byte
15
Base memory low byte
16
Base memory high byte
17
Extension memory low byte
18
Extension memory high byte
19-2d
2E-2F
30
Reserved for extension memory low byte
31
Reserved for extension memory high byte
32
DATE CENTURY byte
33
INFORMATION FLAG
34-3F
Reserve
40-7f
Reserved for CHIPSET SETTING DATA
