Talking of the 380Z...

Tony Duell ard at
Fri Jul 1 17:32:53 CDT 2005

> > The first is the dual cassette controller. The pinout of the 7 pin 


> Hmm... the couple of references I've seen to it in RML documentation
> suggest that it was a 3rd party thing, rather than an RML part. They

I didn;'t get that impression at all....

> talk as though it was some standardised thing built into dual cassette
> drives, or possibly that there was some magic box that sat between the
> 380Z and a pair of standard tape drives.

It's certainly a box that goes between the 380Z's cassette socket and a 
pair of normal recorders. It also would appear (from re-reading the 
minimal instructions I have) that it took power from the 5V output on the 
cassette socket.

It clearly contains a couple of relays and drivers for them (the 'motor' 
lines on the 7 pin DIN socket are outputs from a TTL latch chip). I 
assume it also cnntained switching for the audio signals depending on 
whether one or two recorders were used. But I don't know the details.

Even a list of the front panel controls and connectors would be a start...

> Either way, the impression is that it was nothing to do with RML...

I've never seen any other machine with this sort of cassette connector 
(in particular audio I/O and TTL level motor control lines).

[Bit-banged SIO-2]

> According to the COS 3.4 Reference Manual: "Example programs for driving
> a 20mA or RS232 serial device via the RML SIO-2 and SIO-2B interfaces
> connected to the user I/O port can be found in the Option ROM listing"
> So that might help - if you can find it! I've just checked my pile of
> RML docs and I haven't got a copy of the option ROM listing :(

Incidentally, do you have the COS (monitor ROM) source listings? They 
were available from RML, but I didn't get them with my machine, alas.

There is an example program for reading a tape from an ASR33 in the 
Information File. It would appear that the reader relay is controlled by 
output bit 1, and that RxD comes in on input bit 0. It would be logical 
if output bit 0 was TzD, therefore, but I wouldn't put money on it :-)


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