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General Category => Amstrad CPC hardware => Topic started by: mr_lou on 05:20, 18 August 17

Title: Silly geeky question. Kinda useless, but also a bit interesting
Post by: mr_lou on 05:20, 18 August 17
I've been wondering about this, just for the fun of it:

The CPC464 can read data from tape. We all know how such a tape sounds like. To me, it sounds like a single square synth channel.

The CPC itself can also create square synth audio. So my silly question to the hardware gurus is this:

Theoretically speaking, would the CPC be able to create the audio for another CPC to read?
For example, connect the audio-out of one CPC to another CPC's tape head (possible using an amplifier in-between). Then play audio from one CPC and read it on the other.

Is that doable?
Title: Re: Silly geeky question. Kinda useless, but also a bit interesting
Post by: ervin on 05:22, 18 August 17
I have no idea, but holy cow that would be cool!
(Sorry for this totally useless reply).
Title: Re: Silly geeky question. Kinda useless, but also a bit interesting
Post by: robcfg on 06:29, 18 August 17
You mean that instead of recording a program to tape, if it could be loaded on another CPC?

I guess yes, as the tape is only used as storage for the audio signal.

It would be easy to do a tape to tape cable for 'connecting' two 6128.


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Title: Re: Silly geeky question. Kinda useless, but also a bit interesting
Post by: LambdaMikel on 06:33, 18 August 17
... a simple "network of CPC's"  :D
This is how the "diskless" TRS 80 Model 3 (4) were used in the early 80ies in US classrooms / schools. There was one "master" TRS 80 - the teacher's - and that one would "broadcast" the audio "cassette" data stream to the student's "slave" TRS 80ies.  They had to be inexpensive, hence, no individual disk drives... but each TRS 80 model 3 / 4 had a cassette DIN audio socket.
Title: Re: Silly geeky question. Kinda useless, but also a bit interesting
Post by: PulkoMandy on 07:29, 18 August 17
Yes, a special crossed DIN cable between tape ports of two CPC6128 should just work. You run LOAD on one machine, SAVE on the other, and file transfer happens, basically.


Now, better question: why did no one try this yet?  ;D
Title: Re: Silly geeky question. Kinda useless, but also a bit interesting
Post by: mr_lou on 07:39, 18 August 17
Quote from: PulkoMandy on 07:29, 18 August 17
Yes, a special crossed DIN cable between tape ports of two CPC6128 should just work. You run LOAD on one machine, SAVE on the other, and file transfer happens, basically.


Now, better question: why did no one try this yet?  ;D

Also a groovy idea. That's not what I had in mind though.

This is what I had in mind: Connect the TAPE-IN port of CPC1 to the AUDIO-OUT of CPC2. Then have CPC2 play audio while CPC1 loads the data that the audio represents.

The question is, can the CPC create that kind of audio signal using the 3 channel synth square of that AY chip, that another CPC can interpret as data?
Title: Re: Silly geeky question. Kinda useless, but also a bit interesting
Post by: Bryce on 08:29, 18 August 17
Technically it would work fine, however it would be relatively slow compared to sending digital bits, which is most likely why no-one has ever bothered doing it.

Bryce.
Title: Re: Silly geeky question. Kinda useless, but also a bit interesting
Post by: robcfg on 09:00, 18 August 17
That's an interesting question.


The AY could generate 1000hz and 2000hz signals on any channel, but I think it would be quite tricky to generate the exact number of pulses to encode the information you want to send accurately.


Maybe it would be nice to try as a proof of concept.
Title: Re: Silly geeky question. Kinda useless, but also a bit interesting
Post by: Bryce on 09:27, 18 August 17
Quote from: robcfg on 09:00, 18 August 17
That's an interesting question.


The AY could generate 1000hz and 2000hz signals on any channel, but I think it would be quite tricky to generate the exact number of pulses to encode the information you want to send accurately.


Maybe it would be nice to try as a proof of concept.

There's already a command to create the exact pulses you need. It's called "save", how else do you think a CPC writes to a tape? :D

Bryce.
Title: Re: Silly geeky question. Kinda useless, but also a bit interesting
Post by: robcfg on 09:30, 18 August 17
Sure!


But those aren't generated by the AY chip, which is what Mr. Lou is asking.
Title: Re: Silly geeky question. Kinda useless, but also a bit interesting
Post by: Bryce on 11:11, 18 August 17
It shouldn't be an issue to get the AY to play those tones instead.

Bryce.
Title: Re: Silly geeky question. Kinda useless, but also a bit interesting
Post by: andycadley on 09:46, 20 August 17
Yup. Shouldn't be very difficult, you're just mimicking a 1-bit sample playback. I'd seen people try this with Speccys in the past (which was slightly easier because the LOAD/SAVE connections were externalised)
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