User Guide

Manual Document# 3PXCC4A3001 Appendix A: Hardware I/O A-1
B&B Electronics Mfg Co – 707 Dayton Rd - PO Box 1040 - Ottawa IL 61350 - Ph 815-433-5100 - Fax [phone]
B&B Electronics Ltd – Westlink Comm. Pk – Oranmore, Galway, Ireland – Ph [phone] – Fax [phone]
Appendix A: Hardware I/O Map
I/O Map of XT Class Machines
Hex Address Address Function in XT Class Machines
000-00F
DMA controller (8237A)
020-021
interrupt controller (8259A)
040-043
timer (8253)
060-063
PPI(8255A)
080-083
DMA page register (74LS612)
0A0-0AF
NMI - non maskable interrupt
200-20F
game port joystick controller
210-217
expansion unit
2E8-2EF
COM4 serial port
2F8-2FF
COM2 serial port
300-31F
prototype card
320-32F
hard disk
378-37F
parallel print
380-38F
SDLC
3B0-3BF
MDA - monochrome adapter and printer
3D0-3D7
CGA - color graphics adapter
3E8-3EF
COM3 serial port
3F0-3F7
floppy diskette controller
3F8-3FF
COM1 serial port