Re: iec to pet

Hi,

Okay, I tracked down the problem and updated the schematic... One wire was 
wrong.
http://www.6502.org/users/sjgray/computer/cbm2/cbm2-24k-schematic.jpg

Steve

 


----- Original Message ----
> From: Scott <rylos@charter.net>
> To: cbm-hackers@musoftware.de
> Sent: Fri, October 1, 2010 8:22:19 PM
> Subject: RE: iec to pet
> 
> Dia... Freeware go to http://live.gnome.org/Dia Much better than drawing :) 
> 
> -----Original Message-----
> From: owner-cbm-hackers@musoftware.de
> [mailto:owner-cbm-hackers@musoftware.de] On Behalf Of Steve Gray
> Sent: Friday, October 01, 2010 7:59 PM
> To: cbm-hackers@musoftware.de
> Subject: Re: iec to pet
> 
> Ok, looks like I'll have to re-check the board. Perhaps I missed something,
> like 
> a trace under a chip. I do know that the board works fine.
> Thanks for the feedback.
> 
> Steve
> 
> PS:Can anyone recommend a good free schematic editor? I think I played with 
> Eagle a few years back, but perhaps something new is out now.
> 
> 
> 
> ----- Original Message ----
> > From: "Hoffmann-Vetter, Martin" <martinhv@arcor.de>
> > To: cbm-hackers@musoftware.de
> > Sent: Fri, October 1, 2010 6:25:37 PM
> > Subject: RE: iec to pet
> > 
> > Hello,
> > 
> > > To me, it looks like /WE and /OE will be active together, not usually
> > > a good thing.
> > 
> > Yes, i think there is an error, too!
> > 
> > Because:
> > 
> > /OE = /(SR/W & SPhi2)
> > 
> > That is correct!
> > And:
> > 
> > /WE = /(SPhi2 & /(/OE & /0))
> >     = /(SPhi2 & OE)
> >     = /(SPhi2 & SR/W & SPhi2)
> >     = /(SPhi2 & SR/W)
> >     = /OE
> > 
> > That isn't correct! I Think the logic without U4b is better. Then the
> output
> > from U4d must be short to the input from U4c. So the logik is:
> > 
> > /WE = /(SPhi2 & /OE)
> >     = /(SPhi2 & /(SR/W & Phi2))
> >     = /(SPhi2 & (/SR/W | /Phi2))
> >     = /(SPhi2 & /SR/W | SPhi2 & /SPhi2)
> >     = /(SPhi2 & /SR/W | 0)
> >     = /(SPhi2 & /SR/W)
> > 
> > And that must be okay!
> > 
> > Greetings from Germany
> > 
> > Martin
> > 
> > 
> >       Message was sent through the cbm-hackers mailing list
> > 
> 
> 
>       Message was sent through the cbm-hackers mailing list
> 
> 
>       Message was sent through the cbm-hackers mailing list
> 


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