From: donni (donni_at_com64.com)
Date: 2008-11-27 17:47:34
Why can't you believe that the CIA chip select has to run tru the cartridge
?
Like I said, I reversed engineerd this schematic with a MAX machine in front
of me.
Why commodore did it that way beats me, I can't think of an application that
would benefit from a disabled CIA.
The circuit on the R/W line of the PLA looks like a buffer with a RC filter,
not sure why it is needed.
Maybe to filter out some of the noise on the R/W line?
-donni
----- Original Message -----
From: <ruud.baltissen@apg.nl>
To: <cbm-hackers@ling.gu.se>
Sent: Thursday, November 27, 2008 12:40 PM
Subject: UltiMax schematics
> Hallo allemaal,
>
>
> I'm busy with the SCH and I have a question, but first some facts: the
> 6703 PLA outputs a signal at pin 23 called CIA PLA. The expansion port
> has has two signals called CIA and CIA PLA. The 6526 has a signal
> labeled CIA connected to input CS. And that are all the signals related
> to CIA I could find. According this SCH the 6526 can only be used if an
> cartridge is inserted that connects CIA and CIA PLA, something I hardly
> believe. Can someone shed some light on the case, please?
>
> Then a question out of curiousity: what is the idea behing using
> transistor Q8 in the R/W line towards the 6703 PLA?
>
>
> --
> ___
> / __|__
> / / |_/ Groetjes, Ruud
> \ \__|_\
> \___| URL: Ruud.C64.org
>
>
>
> De informatie in dit e-mailbericht is vertrouwelijk en uitsluitend bestemd
> voor de
> geadresseerde. Wanneer u dit bericht per abuis ontvangt, verzoeken wij u
> contact op te
> nemen met de afzender per kerende e-mail. Verder verzoeken wij u in dat
> geval dit
> e-mailbericht te vernietigen en de inhoud ervan aan niemand openbaar te
> maken.
> Wij aanvaarden geen aansprakelijkheid voor onjuiste, onvolledige dan wel
> ontijdige
> overbrenging van de inhoud van een verzonden e-mailbericht, noch voor
> daarbij
> overgebrachte virussen.
>
> APG Algemene Pensioen Groep NV is gevestigd te Heerlen en is ingeschreven
> in het handelsregister van de Kamer van Koophandel Limburg onder nummer
> 14099617
>
>
> The information contained in this e-mail is confidential and may be
> privileged.
> It may be read, copied and used only by the intended recipient.
> If you have received it in error, please contact the sender immediately by
> return e-mail; please delete in this case the e-mail and do not disclose
> it's
> contents to any person. We don't accept liability for any errors,
> omissions,
> delays of receipt or viruses in the contents of this message which arise
> as a
> result of e-mail transmission.
>
> APG Algemene Pensioen Groep NV is registered in the trade register of the
> Chamber of Commerce Limburg, The Netherlands, registration number:
> 14099617
>
> Message was sent through the cbm-hackers mailing list
--------------------------------------------------------------------------------
No virus found in this incoming message.
Checked by AVG - http://www.avg.com
Version: 8.0.176 / Virus Database: 270.9.10/1815 - Release Date: 11/27/2008
9:02 AM
Message was sent through the cbm-hackers mailing list
Archive generated by hypermail pre-2.1.8.