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Crazy idea for a RS232 mod?

Started by martin464, 11:46, 25 October 22

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Hello, i've lurked on and off just pulled the CPC out the attic (for my son but now I've got hooked again)

Could someone tell me if this idea I had would work?

Using the joystick and printer port you could send and receive 8 bits at a time
Joystick (up/down/left/right + 3 fires), that's 7 inputs + the printer ready signal is your 8 for receiving
The printers 7 bits + the joystick ground is your 8 for sending
I believe the joystick ground's can be software selected to power stick 1 or 2 and act as another output?

You have the printer strobe for some control over it

Then you'd have a pcb that serialises the 8 bits and have it all software controlled direct to a modem
Maybe, what's the point, but I like the idea of it not being an expansion device

Technically feasible?!
Or is there some gotcha that would doom it
CPC 464 - 212387 K31-4Z


Noel made a "hypeloader" for tapes on an arduino via the printer port... using the busy pin as input...

you could use one of the output pins through a serial in/parallel out shift register to get 8bits out in parallel
and the busy pin input coming from the single output of a serial out/parallel in shift get ya data back in..
and the strobe pin to switch direction...

dont quote me a noob when it comes to addons! :P


Sounds all possible, but why? There are enough RS232 designs and devices available that offer RS232 directly from the expansion port and already have supporting software available.



I think to be awkward and difficult?! I seem to have acquired a speciality in this area!

But in my dream setup I have removed the tape drive and installed the DDI-1 PCB in there and plunked in a 512k PCB as well in the space. The expansion port isn't free any more. It has the DDI-1 snaking back inside and glued to the connector is a new port for the floppy drive. Then the whole thing is self-contained except for the external floppy. No worries about jiggling something and crashing the system, which I have done just with a DDI-1 plugged in before

So it's a cheap way to add a modem without disturbing the expansions. I thought it might be cheap to make as well I don't know, but between the software control and the modem the interface might not need to do too much
CPC 464 - 212387 K31-4Z


Even with a DDI-1 inside, it's possible to keep the expansion port free for additional expansions as they (almost) all connect in parallel.



Doable, yes
Effort, too high (lots of precise times software needed)
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