Mongrel edition motherboard thoughts

Open source STF clone project.
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exxos
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Mongrel edition motherboard thoughts

Post by exxos » Tue Oct 23, 2018 2:16 pm

I have a lot of SMT GLUE & MMU currently.. I want to try and make a adapter PCB so they can be used in place of PLCC chips ultimately.. Because probably won't be particularly cheap, but as there is no real alternative currently then it is the only way to supply replacement chips..

But I was thinking that while the motherboard will mostly have FPGA chips replacing them, it is likely going to be a long way off being completed.

So my thought was I could do a inbetween motherboard, which would basically be similar to the board how it is now, but using the SMT GLUE & MMU.. In fact a lot of parts would be SMT on this board, so likely I could actually get these boards assembled to a point myself. Likely I could add in built on DRAM (4MB) would be SMT also.

The thought mostly here is that as like Troed was doing with the DoubleST, that the remake board should be a lot more stable with such a accelerator. Plus the MMU & GLUE are the latest production batch of those chips so likely to be more overclockable than the previous PLCC types.

The main problem with such a overclocked board, is the amount of work it actually needs doing to a original ST where it generally isn't terribly stable overall. But on this new motherboard, it should be more stable and should not really take much more than a small PLD to do the logic for it.

Those who have no idea what I'm talking about, the ST would run at 200% speeds.. ST-RAM runs at 200% as the MMU is overclocked. One side-effect is that the shifter doesn't seem to play nice in mono mode anymore according to Troed's tests so far.

I am not planning on creating such a board any time soon, it is a lot of work, but I see the FPGA stuff taking a lot longer to sort out the way things are going. There is still a lot of mods and things to do on the current board so it will likely be another year even before the current design is finalised finished.

I still have a lot of booster work to finish off yet, so really I need to complete that work before investing a lot of time in the FPGA stuff.

So the mongrel board, would basically be a more SMT based machine with integrated booster and RAM. As there will be a PLD onboard, it can also have TOS206 decoding built in. This chip I would call the "Super GLUE" :)

Ultimately the FPGA GLUE would have all the modifications built into one chip, but again I can just see many problems lining up delaying the next gen board literally by years.

So I think in order to keep work for me down to something reasonable, I think this mongrel board would be the next logical step. I would add in a 68000 DIP socket to take in my SEC booster once completed, and we could probably add in some extra stuff along the way has already talked about..

This does not necessarily mean the current Alpha board would become obsolete. Simply because there would have to be sockets or holes to be able to change the MMU/GLUE etc once the FPGA chip replacements are done. Of course the mongrel edition being more SMT based, would mean the chips would not be changeable.

So I am just thinking out loud more than anything. Of course any modifications or upgrades done on the alpha would go on to the next revision board whatever happens anyway.
4MB STFM 1.44 FD- VELOCE+ 020 STE - 4MB STE 32MHz - STFM 16MHz - STM - MEGA ST - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - HxC - CosmosEx - Ultrasatan - various clutter

https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
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Forgottenmyname
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Re: Mongrel edition motherboard thoughts

Post by Forgottenmyname » Tue Oct 23, 2018 5:52 pm

Hi Chris,

Well I would do my best to help and would likely invest in a board if you made it.

Is it worth using the smt combined blitter too? May free up space.

Of course the main encourage to invest for me would be being able to add in a few of those extras like internal DMA, expansion ports etc,

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Re: Mongrel edition motherboard thoughts

Post by Forgottenmyname » Tue Oct 23, 2018 5:57 pm

Another thought, why not make this board my Mega shaped or ATX shaped, so it's easier to implement?

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Re: Mongrel edition motherboard thoughts

Post by exxos » Tue Oct 23, 2018 6:02 pm

Forgottenmyname wrote:
Tue Oct 23, 2018 5:52 pm
Well I would do my best to help and would likely invest in a board if you made it.
:thumbup:
Forgottenmyname wrote:
Tue Oct 23, 2018 5:52 pm
Is it worth using the smt combined blitter too? May free up space.
It's a interesting thought, I don't know the ins and outs of that chip. The problem is it cannot be used in the proposed overclock mod I was describing :( Plus it is a STE chip, so it would be unable to do TOS104 decoding, at least I assume so.

I was trying to keep the blitter FPGA solution as small as possible, so it could be used on regular ST's , but how it is looking, it is likely going to have to be on much larger board, where likely it will only fit the remake board is because of it. So the blitter will be on his own expansion header instead of a PLCC socket on the board.
Forgottenmyname wrote:
Tue Oct 23, 2018 5:52 pm
Of course the main encourage to invest for me would be being able to add in a few of those extras like internal DMA, expansion ports etc,
Those will be of course added, it is on my to do list.
4MB STFM 1.44 FD- VELOCE+ 020 STE - 4MB STE 32MHz - STFM 16MHz - STM - MEGA ST - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - HxC - CosmosEx - Ultrasatan - various clutter

https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxoshost.co.uk/atari/last/storenew/ - All my hardware mods for sale - Please help support by making a purchase.

troed
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Re: Mongrel edition motherboard thoughts

Post by troed » Tue Oct 23, 2018 6:29 pm

At 5.12V and a heatsink my Shifter (we have a sample population of _one_ so far ;)) was happy with 64Mhz pixel clock (doubleST mono)

However, I think doubleST should have Smonson's FPGA-Shifter. I'll hopefully get back to getting that to work soon.

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Re: Mongrel edition motherboard thoughts

Post by exxos » Tue Oct 23, 2018 6:34 pm

troed wrote:
Tue Oct 23, 2018 6:29 pm
At 5.12V and a heatsink my Shifter (we have a sample population of _one_ so far ;)) was happy with 64Mhz pixel clock (doubleST mono)
Cool, Didn't recall if you got it working or not :)

troed wrote:
Tue Oct 23, 2018 6:29 pm
However, I think doubleST should have Smonson's FPGA-Shifter. I'll hopefully get back to getting that to work soon.
Yeah, Poor shifter isn't to happy with that mod, but if Smonson's FPGA-Shifter can work with it, then all the better. Actually Really need to talk to Smonson about doing a smaller addon board for it...
4MB STFM 1.44 FD- VELOCE+ 020 STE - 4MB STE 32MHz - STFM 16MHz - STM - MEGA ST - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - HxC - CosmosEx - Ultrasatan - various clutter

https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxoshost.co.uk/atari/last/storenew/ - All my hardware mods for sale - Please help support by making a purchase.

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Re: Mongrel edition motherboard thoughts

Post by chlu600 » Tue Oct 23, 2018 7:28 pm

Hi,
First of all I want to thank the current team for your effort with testing and debugging the remakeboard.
I don't have the skills to do it myself. But it has been a great pleasure to follow your work! Hats of! :dualthumbup:

The mongrel edition motherboard sounds like a great idea.
I know that you already have put a lot of time in to this project, and more to come...

Even if I can't build one myself am I interested in supporting this project. That said I'll be a sponsor for the next beta version of the mongrel motherboard :)

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Re: Mongrel edition motherboard thoughts

Post by Forgottenmyname » Tue Oct 23, 2018 7:32 pm

I reckon if Exxos doesn't sleep for the next two weeks, we could have a mongrel board on its way to the makers.

We could place bets on how many ports and pull ups needed fixing as a side line :D

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Re: Mongrel edition motherboard thoughts

Post by exxos » Tue Oct 23, 2018 7:38 pm

chlu600 wrote:
Tue Oct 23, 2018 7:28 pm
First of all I want to thank the current team for your effort with testing and debugging the remakeboard.
I don't have the skills to do it myself. But it has been a great pleasure to follow your work! Hats of! :dualthumbup:
:thanksyellow:

Forgottenmyname wrote:
Tue Oct 23, 2018 7:32 pm
I reckon if Exxos doesn't sleep for the next two weeks, we could have a mongrel board on its way to the makers.
Probably, oddly only sleeping like 2 hours a night the past couple of weeks :roll: Busy sorting out the next PSU batch.. Amazed I've spend a grande on transformers just :roll:

Forgottenmyname wrote:
Tue Oct 23, 2018 7:32 pm
We could place bets on how many ports and pull ups needed fixing as a side line :D
A upgrade by definition is , taking out old bugs and adding in new ones ;)
4MB STFM 1.44 FD- VELOCE+ 020 STE - 4MB STE 32MHz - STFM 16MHz - STM - MEGA ST - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - HxC - CosmosEx - Ultrasatan - various clutter

https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxoshost.co.uk/atari/last/storenew/ - All my hardware mods for sale - Please help support by making a purchase.

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Re: Mongrel edition motherboard thoughts

Post by JezC » Tue Oct 23, 2018 7:39 pm

Likewise, I need to practise my soldering before I risk this sort of project but I would definitely support the next iteration of board (STF remake or Mongrel - or both!).

Better start saving up for it now...

On a vaguely related point, I'm building up an FPGA-based retro computer (6502/6809/Z80) which involves some VHDL so when I've got my head round it again (last used it about 20 years back) I'll try and help with that if I can.

Would be happy to start contributing what & where I can..

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