Re: 6809 in a C64

Den Wed, 23 May 2018 16:00:18 +0200 skrev groepaz@gmx.net:
> Am Mittwoch, 23. Mai 2018, 15:50:03 CEST schrieb Mia Magnusson:
> > Den Wed, 23 May 2018 15:22:44 +0200 skrev Konrad B
> > 
> > <konrad0x42@gmail.com>:
> > > 2018-05-23 14:35 GMT+02:00 Steve Gray <sjgray@rogers.com>:
> > > > Very cool! FYI, the Commodore 64 BTX cartridges also contain a
> > > > 6809, but i haven't seen schematics for them anywhere. They also
> > > > have their own video chip. Other than that, there's really not
> > > > much info out there about them.
> > > 
> > > "BTX Decoder Modul II", the one in REU-like case, has the 6803
> > > MPU and is interfaced to the "main CPU" with the 68HC34 dual port
> > > RAM.
> > 
> > Why were it made that way?
> > 
> > Did the German BTX have some fancy features that the British
> > (Viewdata?) and Swedish Teledata never had?
> 
> IIRC it originates from typical german regulations - ie "software"
> decoders were illegal at the beginning, only certified devices were
> allowed to be used with BTX.

We had that kind of regulations too, but sometime in perhaps 83-84 third
party vendors could get their modems approved, so Handic/Datatronic got
their modem for C64 approved. I guess that this was partially due to
the telco wanted people to get on to their "Datavision" service.

Afaik there were no special regulation on actual usage of the
Datavision (Swedish national monopoly telcos BTX/Viewdata/Prestel
service), only that the modem had to be approved for connecting to the
public telephone network. Btw for some reason the Swedish post (totally
separate from the telco right from the start) had their own Prestel
service. I don't know why (, and I also don't know why they started a
web site in the 90's as it didn't generate any revenue for them, while
the telco operated website generated dialup traffic)...

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