ZiLOG Z80 User Manual

12
SW1
Image Qty Reference Description
1
SW1 DIP switch,6 way,piano style
Supplier Partnumber
eBay 262361463572
Farnell 2452331
Mouser 653-A6FR-6104(black)
RS 877-2359
Thisswitch isused toset the I/Oaddress for the module.It sets therequiredstateof
address linesA2 toA7, thus allowing themodule tooccupy a 4address block onany
4-byteboundary.
Inorder to provide somecertaintyfor software itis strongly recommendedyou set
the base addressof your first PIOmoduleto 0x68, sothat themoduleoccupiesI/O
addresses 0x68to 0x6B. This is doneby setting switches 1to6, to On, Off,Off, On,
Off,On where Onis the switch closed.In the caseof thepiano style DIP switch, the
Onposition isthe switch lever pusheddowntowardsthe circuit board.
Switchesin theOn positionpull down the input of theaddress comparatorU1.
Switchesin theOffposition allow theinput ofthe address comparatorto be pulled
up byRP1.
U1
Image Qty Reference Description
1
U1 74HCT688, 8-bitidentitycomparator, PDIP20
Supplier Partnumber
Farnell 2407104
Mouser 595-CD74HCT688E
RS 663-0650
Thisintegrated circuitprovides the address decoding, bycomparing thecurrent
address from theCPUwith the address set withthe DIPswitch SW1.

ZiLOG Z80 Specifications

General

Brand	ZiLOG
Model	Z80
Category	Computer Hardware
Language	English