Ethernet for the QL

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Dave
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Re: Ethernet for the QL

Postby Dave » Sun Mar 14, 2021 8:11 pm

I've been thinking abut this some more, and an internal unit doesn't even need to occupy the slot. It could sit in the CPU socket, and have access to all needed address, data and control lines. Including memory. That way, SGCs would act completely as normal, and it could work standalone too. Replacing the 68008 with a 68000 in 8-bit mode would open up larger memory options, too. 16MB theoretically.


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Re: Ethernet for the QL

Postby Derek_Stewart » Mon Mar 15, 2021 8:59 am

Dave wrote:I've been thinking abut this some more, and an internal unit doesn't even need to occupy the slot. It could sit in the CPU socket, and have access to all needed address, data and control lines. Including memory. That way, SGCs would act completely as normal, and it could work standalone too. Replacing the 68008 with a 68000 in 8-bit mode would open up larger memory options, too. 16MB theoretically.

I always remove the 68008 when using a SGC or GC, it does not serve any purpose having the 68008 in the CPU socket.

I always though an extra expansion port could be made to plug into the CPU and 8301 sockets, the ROM port connector could be moved to the new expansion port and have a integrated expansion connector. Maybe this is a way forward.

I will see if I can find time to do a prototype.


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Dave
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Re: Ethernet for the QL

Postby Dave » Mon Mar 15, 2021 3:48 pm

We installed a few Sandy (not SPEM) internal RAM expansions and the failure rate was very high. Arnie Gardner looked into the problem and found it was caused by the difference in height between the CPU and 8301 socket. The CPU socket was of really poor quality. It was ok if used by itself, but with the different height of the 8301 socket, the CPU socket always released whatever it was holding. We never released that expansion.

So CPU or 8301 replacement PCBs are ok, but if anything touches both it is doomed. Doomed I say!


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Re: Ethernet for the QL

Postby Dave » Wed Mar 17, 2021 4:45 pm

Prototype large PCBs ordered. I ordered 10 as it costs the same as 5.

The miniature internal version will make the assumption that people already have RAM expansion or an (S)GC so it skips the internal memory expansion entirely. It uses the 68008 socket and places the components far inside the case. I'm looking for a shallow panel mount ethernet jack to go with it. The nice thing about this is it will work with the internal CPU in place or not. (S)GC cycles that access the QL will still see the interface. I'll work on the mini version to put in a future PCB order once I confirm the logic of the large version.


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Re: Ethernet for the QL

Postby Peter » Wed Mar 17, 2021 8:04 pm

Dave wrote:It uses the 68008 socket and places the components far inside the case.

Sounds very interesting! You will need a socket with long pins - isn't that a problem for 48 pin sockets? Or would you replace the CPU also?


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Re: Ethernet for the QL

Postby mk79 » Wed Mar 17, 2021 9:56 pm

Peter wrote:Sounds very interesting! You will need a socket with long pins - isn't that a problem for 48 pin sockets? Or would you replace the CPU also?
I recently ordered a bunch of MPE-GARRY 006-1-032-D-B3STF-XS0. Best pins for such a task, just frigging expensive.


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Re: Ethernet for the QL

Postby Dave » Wed Mar 17, 2021 9:56 pm

Peter wrote:Sounds very interesting! You will need a socket with long pins - isn't that a problem for 48 pin sockets? Or would you replace the CPU also?

SMD mounted turned pins on the lower side of the board, leaving the top side completely free. Safest way to get a good electrical connection without ruining the socket, AND giving the board a chance to be compact enough to not constantly work loose.


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Re: Ethernet for the QL

Postby Peter » Mon Mar 22, 2021 2:20 pm

mk79 wrote:I recently ordered a bunch of MPE-GARRY 006-1-032-D-B3STF-XS0. Best pins for such a task, just frigging expensive.

Indeed. € 4,23 and one needs two of them. But at least a possibility.

Dave wrote:SMD mounted turned pins on the lower side of the board, leaving the top side completely free.

How can you leave the top side completely free with the 68008 plugged in?


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Re: Ethernet for the QL

Postby Dave » Mon Mar 22, 2021 6:05 pm

Peter wrote:How can you leave the top side completely free with the 68008 plugged in?


Replace the DIP 68008 with a PLCC one. I have hundreds. It also gives the option of just leaving it off if it's being used with a SGC.


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Re: Ethernet for the QL

Postby Peter » Mon Mar 22, 2021 10:45 pm

Dave wrote:Replace the DIP 68008 with a PLCC one. I have hundreds.

That's why I initially asked if you'd replace the CPU also. It was not totally obvious for me that you own hundreds of PLCC 68008. ;)
These CPUs are probably cheaper than the sockets mentioned above?



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