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Path: utzoo!watmath!clyde!akgua!sdcsvax!sdcrdcf!hplabs!hao!seismo!brl-tgr!spangler
From: spangler@brl-tgr.ARPA (James J. Spangler )
Newsgroups: net.micro.zx
Subject: Reply on how to drive leds
Message-ID: <4868@brl-tgr.ARPA>
Date: Tue, 25-Sep-84 09:12:40 EDT
Article-I.D.: brl-tgr.4868
Posted: Tue Sep 25 09:12:40 1984
Date-Received: Sat, 29-Sep-84 09:56:26 EDT
Organization: Ballistics Research Lab
Lines: 9


 I have been expermenting with zx81's and find that using a 8255 I/O chip
is the best way for me. It has 24 I/O lines that  can drive a 5 volt logic
level, which can be used to drive leds, scr's, and triac's. 
 Besides using the 8255 you would need address decoders, which can be done
with a 74LS138 and a few other 74's. I have also tried voice interfacing
using the GE SP-0256 which seems to work well.     

                                                         Jim