USB Comms Adapter

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amenjet
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Joined: Sun Aug 22, 2021 6:56 am

USB Comms Adapter

Post by amenjet »

I'm in the middle of laying out a prototype USB comms adapter and wondered if there were any comments or requests. The circuit I'm using has a flash ROM which is several (8) times larger than the 32K that is needed for a comms link ROM. I was wondering if it's worth putting links on the PCB so different images can be selected. If so, what images? The ROM is not programmable on the PCB so changing the images would be a bit of a faff.
Also, if the PCB was populated with no USB circuitry then it could be used as a ROM carrier and have different images to set different settings or whatever.

After thinking about the above I realised that it might be possible to create a USB link using the RP2040 chip (as used in the SD card datapak). That has the advantage of:

1. Being cheap (89p)
2. Being modern and not obsolete as the flash ROM chip I'm using is.
3. Programmable from the USB so different images can be sent as required.
4. Being an intelligent device it has the ability to do different things.
5. Unlike the SD gadget it can be powered from the USB so needs no extra wiring.

Cons:

1. I haven't managed to get USB and ROM decode working on an RP2040 yet, but I'm pretty sure it's possible.

So, at the moment I'm thinking I will do both adapters due to the Con above meaning the RP2040 version may never work. Any comments?

Andrew
Cosi1125
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Re: USB Comms Adapter

Post by Cosi1125 »

Is it possible to extend the functionality of the original Comms application that comes bundled with the Comms Link? I'd love to have the option to bulk-copy files...
amenjet
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Re: USB Comms Adapter

Post by amenjet »

Cosi1125 wrote: Sat Aug 06, 2022 6:16 pm Is it possible to extend the functionality of the original Comms application that comes bundled with the Comms Link? I'd love to have the option to bulk-copy files...
That's a function of the code so the comms application would need to be disassembled, examined and augmented. All do-able, just a bit time consuming. there may not be space in the ROM for the extra features so a different ROM might be needed. In that case an easily switchable ROM image facility would be useful.
How would you specify the bulk files? using wildcards?

Andrew
Cosi1125
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Re: USB Comms Adapter

Post by Cosi1125 »

Just like this tool does. You can transfer all the matching files at once or one-by-one (the already transferred files are marked with a symbol).
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Lostgallifreyan
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Re: USB Comms Adapter

Post by Lostgallifreyan »

There's an equivalent of the Win32 API's 'FindFirstFile' function in the Organiser services. It may be overlooked sometimes because it's so primitive but it takes wildcards and is the basis for most of the more familiar methods in systems various. The fact that this specific method exists in almost exactly equivalent form in a modern Windows machine, and the Psion Organiser 2 is something I found very comforting, it means we can probably trust it to exist almost anywhere, in anything, from any time in computing history. I like stuff like that.

About the extra ROM, I think that unlike OPL's direct access, it may be possible to arrange (using machine code and services) to access slot D like an ordinary pack. If so, it may be possible to host a flash driver, FNKEY, and maybe Jaap's main TSR's for easy install when setting up an organiser, to free up space elsewhere in normal use. 256K of space in an adapter seems like a good place to make a 'start-up' pack for rapid setup of an Organiser.
amenjet
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Re: USB Comms Adapter

Post by amenjet »

The top slot 'doesn't support ROMs larger than 32K as it uses the basic signals for ROM access and is assuming that external hardware is using the other lines. You could probably get some more space by using some of the lines for paging. Some lines are needed for the serial interface so that sort of puts a stop to that.
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Lostgallifreyan
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Re: USB Comms Adapter

Post by Lostgallifreyan »

That sounds severe enough to end any practical use of extra ROM space for the Organiser itself, even switching to a different ROM might not be useful unless a new ROM were written because the latest of the originals is fairly definitive.

In the post I made about new Organiser developments aimed at keeping the original power demand limit strictly observed so there are modern developments helping to show how computing in this way is viable in a world all but set to tear itself back to the stone age, assuming a climate-driven mass extinction does not drive us into complete oblivion, there would be a critical need to demonstrate ways an Organiser can be relevant. People's expectations MUST change if we are to survive this, so it's down to who can shape these expectations, and how.

I mentioned that audio and radio devices might be built into adapters, controlled by software on the Organiser. Some devices may even be built into packs, though getting adequate power and signals might be a big limitation on using that format!

Assuming that the adapter IS a host for Organiser-controlled devices with much more elaborate and specific capability, you could use some of that extra ROM space to support those, if shared addressing schemes can be devised.

---------

About my earlier post, it's not helpful, I came back to delete it but I saw you'd answered it so I won't, but I did check that wildcard-search thing, and as far as I know only the LZ has services that can do it, and those seem to mostly have an OPL equivalent. Unless machine code were copied or written from scratch, there may be no generic way for all series 2 machines.

EDIT:
Who, or what, is Amenjet? He sounds like he might have either designed a pyramid in Giza, or been buried under one. Or both... Are you a fan of Iron Maiden? 'Powerslave' comes to mind. :) I like playing that on a bass..
Cosi1125
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Re: USB Comms Adapter

Post by Cosi1125 »

<offtopic>
Hello, fellow Maiden fan :D
</offtopic>
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Lostgallifreyan
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Re: USB Comms Adapter

Post by Lostgallifreyan »

I knew there'd be one somewhere. :) Early Stranglers too, perhaps? (Short post; as you say, not really why we're here. (Though it might be worth having some kind of spieler subform so we can do this at length.. Some place to invoke parlay at times..)
amenjet
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Re: USB Comms Adapter

Post by amenjet »

Lostgallifreyan wrote: Sun Aug 07, 2022 11:09 am That sounds severe enough to end any practical use of extra ROM space for the Organiser itself, even switching to a different ROM might not be useful unless a new ROM were written because the latest of the originals is fairly definitive.
Well, there may be enough 'state space' left to switch a ROM or provide a larger ROM. Maybe.
In the post I made about new Organiser developments aimed at keeping the original power demand limit strictly observed so there are modern developments helping to show how computing in this way is viable in a world all but set to tear itself back to the stone age, assuming a climate-driven mass extinction does not drive us into complete oblivion, there would be a critical need to demonstrate ways an Organiser can be relevant. People's expectations MUST change if we are to survive this, so it's down to who can shape these expectations, and how.
I think it's been demonstrated that there's no will to do anything quickly and we're going to have to go down the route of mechanical extraction of CO2 from the atmosphere and storage thereof. But even that isn't going to happen until things get worse IMHO
I mentioned that audio and radio devices might be built into adapters, controlled by software on the Organiser. Some devices may even be built into packs, though getting adequate power and signals might be a big limitation on using that format!
Power is definitely a problem for packs, the top slot not so much. I have hardware for both that can be attached to arbitrary items.
Assuming that the adapter IS a host for Organiser-controlled devices with much more elaborate and specific capability, you could use some of that extra ROM space to support those, if shared addressing schemes can be devised.

---------

About my earlier post, it's not helpful, I came back to delete it but I saw you'd answered it so I won't, but I did check that wildcard-search thing, and as far as I know only the LZ has services that can do it, and those seem to mostly have an OPL equivalent. Unless machine code were copied or written from scratch, there may be no generic way for all series 2 machines.
I was assuming writing something, perhaps after an IDE so it is easier to do....

EDIT:
Who, or what, is Amenjet? He sounds like he might have either designed a pyramid in Giza, or been buried under one. Or both... Are you a fan of Iron Maiden? 'Powerslave' comes to mind. :) I like playing that on a bass..
'amenjet' is just the first letters of my first and last name {amen) and 'jet' comes from the fact that my surname is Breton (or Cornish or Welsh) for black rock, which specifically was used for the semi precious stone jet. So, no, not Maiden.
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