B&B Electronics PC Watchdog Timer Card ATRWDT User Manual page 21

Hex Address
000-01F
020-03F
040-05F
060-06F
070-07F
080-09F
0A0-0BF
0C0-0DF
0F0-0FF
1F0-1F8
200-20F
258-25F
278-27F
2E8-2EF
2F8-2FF
300-31F
378-37F
380-38F
3A0-3AF
3B0-3BF
3BC-3BE
3C0-3CF
3D0-3D7
3E8-3EF
3F0-3F7
3F8-3FF
Any eight-byte space not listed above or not used by any
other equipment in your system may be used by the WDT.
A-2 Appendix A
I/O Map of AT Class Machines
Address Function in AT Class Machine
DMA controller #1 (8237A-5)
Interrupt controller #1 (8259A)
timer (8254)
Keyboard (8042)
NMI – non maskable interrupt & CMOS RAM
DMA page register (74LS612)
Interrupt controller #2 (8259A)
DMA controller #2 (8237A)
80287 math coprocessor
hard disk
game port joystick controller
Intel Above Board
parallel printer port 2
COM4 serial port
COM2 serial port
Prototype card
parallel printer 1
SDLC or bisynch com 2
bisynch com 1
MDA – monochrome adapter
parallel printer on monochrome adapter
EGA – reserved
CGA – color graphics adapter
COM 3 serial port
floppy diskette controller
COM1 serial port
Documentation Number ATxWDT-1303