Ethernet for the QL

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Dave
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Re: Ethernet for the QL

Post by Dave »

Surprisingly true.

Summer here is mostly days in the mid 40s, with humidity up over 80% during the day and 100% at night. At 3am it sometimes gets down to 32C/ It's not conducive to projects, so I just go on road trips to Colorado or Arizona. The whole COVID situation means I haven't had that element in my life for 16 months, so the second I was vaccinated and every state was open that I wanted to pass through, I jumped on the change for a bit of shoulder season tourism before EVERYONE ELSE does the same thing.

Peter: The 2200 can only handle the magnetics being up to about 40mm away and then it all goes to hell. I have the RJ45 with the magnetics built in. Are you aware of any separate magnetics that have the same characteristics? If I can identify some, I can use those and a standard RJ45, allowing it to be much further from the board. The dimensions of the ones I have are really restrictive as they're larger than ordinary RJ45s.


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Peter
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Re: Ethernet for the QL

Post by Peter »

Suitable separate magnetics certainly exist. But I never selected any, since I prefer them integrated.
Not sure what you mean by "up to about 40mm away and then it all goes to hell".
The signals are differential, so if you have a groundplane and keep them in pairs, I don't see why the CP2200 should be so restrictive.


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Re: Ethernet for the QL

Post by Dave »

If the magnetics are close to the IC it works fine. I was trying to put them on a short cable so the socket could be located somewhere with more room (can't close the case) but the signal is destroyed. The datasheet also says the magnetics need to be within 3-4cm of the IC.

I've ordered a revised PCB that solves this conflict. Also fixes a missing JTAG line.


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Re: Ethernet for the QL

Post by Dave »

Expanding on my previous comment:

I placed the jack facing left towards the expansion port. Even very gentle wiggling of the cable makes the board jump out of the socket. The CPU sockets are UTTER CRAP. I will try with it facing backwards (exiting the ROM port) to see if the reduction of leverage helps. If it doesn't, it will have to go elsewhere.

I used turned pins, as I do not want to de-spring the leafs. I could use square pins but they would ruin the socket for anything else that follows. The SPEM internal 512K used to do that too. So obviously that's not an option.

I'll drop the schematic onto a small expansion bus card just to get the testing out of the way. A couple more weeks?

I hope that explains a bit better what's going on.


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Peter
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Re: Ethernet for the QL

Post by Peter »

Dave wrote:I was trying to put them on a short cable so the socket could be located somewhere with more room (can't close the case) but the signal is destroyed.
I was not aware you were using a cable. That is of course problematic.
Dave wrote:The datasheet also says the magnetics need to be within 3-4cm of the IC.
From what I read, it's not that strict. They say it "should" be for "optimal performance". With decent differential tracks and ground plane I'm sure at least twice of that is no problem. But since you didn't mean to stay on PCB, that does not help of course.
Dave wrote:I placed the jack facing left towards the expansion port. Even very gentle wiggling of the cable makes the board jump out of the socket. The CPU sockets are UTTER CRAP.
Sorry to read you have so much trouble.

I also have no good ideas for a compact mechanical solution with (S)GC systems.


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Re: Ethernet for the QL

Post by Derek_Stewart »

Hi,

Just copied these messages to the Ethernet for the QL message thread.
XorA wrote: Sat Feb 18, 2023 9:20 pm This is very not vapourware BBQL network! :-D

Image

But do give us some time on the drivers, life is getting in the way!
ppe wrote: Sat Feb 18, 2023 8:48 pm
Derek_Stewart wrote: Sat Feb 18, 2023 6:23 pm Just a pity, the QL Ethernet never appeared, as we could of had a 10Mb QL NETwork.
Having received a couple of messages expressing interest in my (now very) old prototype project I spent some time and converted it to a PCB rev 1 a couple of months ago:
Image
There's going to be at least one more revision coming up once we understand what we need from the SW side.

Currently has a DNS resolver, DHCP client, and TFTP client. And socket-level C code that can be linked in to other SW. Driver for SuperBasic needs a bit of an overhaul but there are persistent rumours of it being a joint effort and not just me any more. Tim and Dilwyn's SuperBasic IRC client works already. And just for lulz I wrote a very limited SuperBasic FTP client. Full support for IPBasic extensions are a distant goal.

Runs on BBQL and SGC, Havent't figured out if there's a way to make it work with a GC. Last time I asked on the forum the consensus seemed to be that there is no way to make an extension card work with a GC. I would very much like to understand if the expansion ROM slot address space could be grabbed from GC's grubby hands but I don't have a GC so there's no way for me to experiment with this. Essentially I would just need 2k of memory mapped IO but GC is greedy.

I've hand-soldered a few boards and sent them to contributors. I have no intention of selling this but it's going to be open source so group orders would be totally feasible should someone be interested.

Cheers,
Petri
I note that the Ethernet card connects to the QL expansion port with a Backplate, is this the Tetroid one, which is not available.

Could the MiniBack Plate idea to fit the board inside the QL Case work?

See:
Mini Backplane2.jpg


Regards,

Derek
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ppe
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Re: Ethernet for the QL

Post by ppe »

Derek_Stewart wrote: Sun Feb 19, 2023 8:59 am I note that the Ethernet card connects to the QL expansion port with a Backplate, is this the Tetroid one, which is not available.

Could the MiniBack Plate idea to fit the board inside the QL Case work?
Yes, currently, with the Wiz830MJ off-the-shelf daughterboard module you do need some way to get the card outside the QL case, be it a through-connector memory expansion card or a backplane extender like XorA and myself are using.

Ditching the daughterboard and moving the components to the PCB proper would save some vertical space but the Ethernet MagJack connector is quite high, roughly 13mm, which means that at least that component should probably sit outside the case if a MiniBack was in use. I would need some help understanding the mechanical constraints to better see the ramifications.

Current daughterboard approach makes sense during development since the daughterboard module can easily be moved to a new revision of the PCB. For a more mature version integrating all the components on the PCB would probably be the "right" approach.

Thank you for your insight, Derek!

Kind regards,
Petri


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Peter
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Re: Ethernet for the QL

Post by Peter »

Derek_Stewart wrote: Sun Feb 19, 2023 8:59 am Just copied these messages to the Ethernet for the QL message thread.
Although I picked quite a general title for this topic, it was practically focussed on a specific chip, the CP2200. While I still think that the existence of Q68 drivers and the nature of the CP2200 bus interface makes it a quite realistic choice for the QL, it suffers from two drawbacks:
1. Although the circuitry would not be too difficult, there is currently noboby who brings it to PCB and PLD.
(It would be unwise to do it myself, while I have other unfinished projects.)
2. Since the network stack is running on the 68K side, it is quite demanding in terms of native CPU / memory speed.

I have the impression that Petri's project has the edge on both. It is surely interesting enough to deserve it's own discussion.
I don't remember if it already had a topic on this forum. If not, it should have.
XorA wrote: Sat Feb 18, 2023 9:20 pm This is very not vapourware BBQL network! :-D
Absolutely. My own philosphy has always been somehat against offloading software to non 68K CPUs. But it can simply be more practical. Especially if there is a person behind it, who already has developed things as much as Petri.
XorA wrote: Sat Feb 18, 2023 9:20 pm But do give us some time on the drivers, life is getting in the way!
That still might speak more for the CP2200, but see above...
Derek_Stewart wrote: Sat Feb 18, 2023 6:23 pm Just a pity, the QL Ethernet never appeared, as we could of had a 10Mb QL NETwork.
Yes, but keeping in mind that QL, GC and SGC will not even have a third of that actual throughput. Let alone mass storage file reads over network, where every native QDOS/SMS system suffers greatly from the terrible SLAVE buffering. Even the fastest hardware, the Q60, suffered so much that full ethernet speed was only possible under Linux, or if memory was artificially taken away from QDOS/SMS so it can not do the buffering.


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Peter
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Re: Ethernet for the QL

Post by Peter »

ppe wrote: Sun Feb 19, 2023 9:54 am Ditching the daughterboard and moving the components to the PCB proper would save some vertical space but the Ethernet MagJack connector is quite high, roughly 13mm, which means that at least that component should probably sit outside the case if a MiniBack was in use.
Independent from CP2200 or Wiz830MJ as controller, finding a good place for the jack in (S)GC systems remains a major problem. I never found a satisfying solution. Which contributed to reduced interest in designing a PCB myself.


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Re: Ethernet for the QL

Post by ones' complement »

Since the Pico worked a minor miracle for QL VGA (thanks to Oliver), is it possible WIZnet W5500-EVB-Pico - RP2040 Board with Ethernet might be useful here (or am I being a bit naive :oops: ).


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