Date   : Fri, 26 Nov 2010 12:36:04 +1100
From   : plexer@... (James McGill)
Subject: Electron Ferranti ULA reverse engineering progress

I don't suppose you know of any resources for the BBC's 1200 baud
cassette interface? My best guess is that the analog cassette signal
is quantized to a digital signal and then processed in software, but I
can't find anything concrete. Most of the circuits I can find that
deal with cassette recordings implement the 300 baud standard, and
usually mostly in hardware.

Regards,
James

On Fri, Nov 26, 2010 at 12:26 PM, Philip Pemberton
<philpem@...> wrote:
> On 26/11/10 01:13, James McGill wrote:
>>
>> Hi Ed,
>>
>> Can you tell me if it has much about the 1200 baud cassette decoding
>> circuitry? This is something I'm interested in understanding, and
>> would on its own be worth picking up a copy.
>
> Eight pages on the cassette interface in total -- one 6-page chapter on
> cassette out / speaker, and a few pages about the cassette I/O circuitry in
> the previous chapter.
>
> It's basically a single I/O pin, all the decoding is done in software.
>
> I think the TOC is on Chris's website somewhere... perhaps as part of the
> "sample chapter" PDF?
>
> --
> Phil.
> philpem@...
> http://www.philpem.me.uk/
>