Path: utzoo!attcan!uunet!mcsun!sunic!luth!eru!bloom-beacon!tut.cis.ohio-state.edu!ucbvax!HASARA5.BITNET!ROBBEL%NKIVXH.SURFNET
From: ROBBEL%NKIVXH.SURFNET@HASARA5.BITNET ("Robert Belleman, Amsterdam")
Newsgroups: comp.sys.apple
Subject: RE: Re: Apple 2e doesn't see my 6522's !!
Message-ID: <8909110452.aa14213@SMOKE.BRL.MIL>
Date: 11 Sep 89 09:52:00 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 46

>In article <8909060935.aa25446@SMOKE.BRL.MIL>
> ROBBEL%NKIVXH.SURFNET@HASARA5.BITNET writes:
>>        2 VIA's and one 74LS138 3-to-8-decoder for address-decoding:
>>        A4 - A5 - A6 connected to input lines,
>>        A7 to first enable (active low),
>>        _________
>>        IO-SELECT to second enable (active low),
>>        third enable to +5V (active high).
>>        Output 1 of the LS138 is connected to VIA-1, output 2 to VIA-2.
>>        A0 to A3 are connected to R(-egister)S(-elect)0 to RS3 of both VIA's.
>>        As a clock I'm just using Phi-0 (I also tried inverted Phi-1 but that
>>        didn't work either). No patching done to the clock.
>>The interface should be in the address range $C700 to $C7FF (if I put it in
>>slot 7; VIA 1 : $C700-$C70F,  VIA 2: $C710-$C71F) but there's nothing there !!
>
>Sounds pretty reasonable to me.  When you say "nothing is there" for $C700-1F,
>are you getting the same random-ish stuff you get when the card isn't plugged
>in at all, or something else?

I get the same random stuff if the card is un-plugged.

>You didn't mention the D0-D7 signals, but I assume you've just connected them
>straight to the VIAs.

What!? You mean I have to connect D0-D7 ???  Sorry. Just kidding; I have:
straight to the VIA's, no buffers.

>(I don't have the 6522 specs right in front of me...what
>are you doing with the clock?  Just running it to "clock" inputs on the 6522s?)
                                 _
Yep, I just connected it to the 'E' input of the 6522.

I think I'll have a go at that little circuit-hack Stephen, Dick and Tom were
talking about. I'm pretty sure now it's a clock problem. I'll let you guys
know if it turned out.
Thank you all very much for your help, Dick, Tom, Dave, Stephen and all others
who have replied but I haven't received yet ...

Robert Belleman, the Netherlands Cancer Institute Amsterdam.

-------------------------------------------------------------------------------
'He whom whispers their |       ROBBEL%NKIVXH.SURFNET@HASARA5.BITNET
 fate into the  ears of |       ROBBEL%NKIVXH.SURFNET@SARA.NL
 lobsters is bound to   |       ROBBEL@VAXH.NKI.NL
 get nipped.'           |       PSI%02041291011::ROBBEL
-------------------------------------------------------------------------------