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STE / MSTE 68020 booster

Posted: Mon Jan 15, 2018 9:30 pm
by rpineau
As some of you might now, me (Rodolphe) and Juliusz have been working on a 68020 card for MSTE and STE.
I started on my own and the first version only had the 68020 and a CPLD to do the signal adaptation and eventually run at 16MHz and 32MHz.
Assembled_front.png
Assembled_front.png (137.21 KiB) Viewed 10738 times
We got this working but the CPLD was not working as expected and we had a lot of issues with the CPLD dev tools.
After getting this version working we took the time to re-assess the CPLD situation and decided to use a different brand.
We're now using Xilinx XC9500XL series.
After this we designed a new version with the new CPLD (Xilinx XC95144XL) as well as 2 socket to put a 32bit TOS on it, an expansion port that used "normal" header instead of the expensive DIN41612 connector.
MSTE_020_V2.1.png
MSTE_020_V2.1.png (875.63 KiB) Viewed 10738 times
We got a few PCB made and assenbled 2 MSTE cards (which also works in Juliusz STE).
We got these working fairly quiclky and even got the 16MHz and then 32MHz working on these.
After that we also go the TOS to work in 32 bit. We also have the TOS working with the blitter (aka blitter accessing the TOS on the board in 2x16 bit transfer).

Of course we ran into countless issues with bus mastering (blitter/dma) and wai state, sync and what not.
We think we have it working well now and Juliusz think he solved the last few issue he had with the CosmosEx RPI communication (the SD card side has been working fine for a long time on my MSTE and his STE).
We also had a few PCB issues, bad board, track or via peeling off.. so all of this slowed us down (and life stuff got in the way too).

We are now starting to assemble version 3 for the board for this project. We once again changed the connector for something modern that doesn't take too much space (AMP 5-5179009-5 120 pin 0.8mm 2 rows).
We also put a bigger CPLD (XC95288XL TQFP144) to integrate an interrupt controller on the card for the expansion card. We plan on using the VHDL code from the MFP68901 from the Suska project and trim everything we don't need to only keep the 8 external interrupt pin. The advantage is that Atari coders already know how to use the MFP and it will be "wired" at the same address as the 2 MFP on the TT.
I don't yet have a proper picture of the new v3 board (STE or MSTE).

We will release all of this as open-source once the V3 are tested and working like the V2 and will update the VHDL code as we go for the interrupt controller.

We also looked at the STFM and Mega ST. I made a DIL to PLCC adapter so we can test the card in a MegaST and potentially in a STFM. We haven't had time to test this yet.

I'll try to update this post as we make progress.
Rodolphe

Re: STE / MSTE 68020 booster

Posted: Mon Jan 15, 2018 10:26 pm
by rpineau
As said I don't have picture of theV3 board but I can post images of the PCB in Eagle :).

MSTE V3 :
MSTE_V3.png
MSTE_V3.png (90.6 KiB) Viewed 10731 times

STE V3 :
STE_V3.png
STE_V3.png (95.94 KiB) Viewed 10731 times

Re: STE / MSTE 68020 booster

Posted: Mon Jan 15, 2018 10:31 pm
by exxos
great news for 2018 :thumbup:

Re: STE / MSTE 68020 booster

Posted: Mon Jan 15, 2018 11:40 pm
by arf
rpineau wrote: Mon Jan 15, 2018 10:26 pm As said I don't have picture of theV3 board but I can post images of the PCB in Eagle :).

MSTE V3 :
MSTE_V3.png


STE V3 :
STE_V3.png
Great news, cool! Please don’t count this as criticism (any accelerator in my MegaSTE will be better than none, and yours definitely looks cool!), but why a 68020 and not a 68030?

Re: STE / MSTE 68020 booster

Posted: Tue Jan 16, 2018 2:31 am
by rpineau
Well .. who said we didn't try a 68030 on that board :) .. with a small adapter :)
We want to get it all working first and moving to the 68030 is almost just a CPU swap in the schematics..... and who said I don't already have an Eagle schematic with the 68030RC50 :) ....
And .. I had a small pile of 68020 to use.. and no 68030 at hand when I started.
TOS 2.06 is more for 68000, 68010. It works ok on a 68020 and 68030 so we chose the 68020 on TOS 2.06 for now as it doesn't require any patching of the TOS
A 68030 would work a lot better on a TOS 3.06. The TOS 3.06 would need to be patched for STE/MSTE (and STFM/ Mega ST).
As I said.. it will be all open-source so people can chose to build one or the other based on their needs, the 68020 being more "compatible" than the 68030 for games .

If no one wants the 68020 may be we'll go straight to 68030 (but they are more expensive and harder to find) as they can go to higher frequency (max freq for 68020 is 32MHz before overclocking, max speed for 68020 is 50MHz before overclocking).

On the "other forum", people have been able to recompile TOS from the original sources.. but with old compiler chain and it looked painful.
If we can get this all converted to GCC (and GASM) with a proper Makefile to use with a cross-compiler we could customize the TOS to work better with the accelerators (not just this one). But this is probably a subject for another post somewhere on this forum.

And don't worry, all comments are welcome. Criticism is not an issue as long as it's constructive criticism.

Regards, Rodolphe

Re: STE / MSTE 68020 booster

Posted: Tue Jan 16, 2018 2:33 am
by rpineau
more teasing :
68020_030.png
68020_030.png (19.28 KiB) Viewed 10711 times

Re: STE / MSTE 68020 booster

Posted: Tue Jan 16, 2018 6:57 am
by Icky
:bravo: great work. I had noticed your 68020 booster on exxos’ lastupgrade site a long time back. I had wondered what became of that effort. Glad to see it’s still alive and looking forward to reading progress about it.

Re: STE / MSTE 68020 booster

Posted: Tue Jan 16, 2018 9:08 am
by Cyprian
rpineau wrote: Tue Jan 16, 2018 2:31 ammay be we'll go straight to 68030
+1 for 68030.

Re: STE / MSTE 68020 booster

Posted: Wed Jan 17, 2018 10:35 pm
by arf
rpineau wrote: Tue Jan 16, 2018 2:31 am Well .. who said we didn't try a 68030 on that board :) .. with a small adapter :)
Ops, I didn’t say a-n-y-thing. :D
rpineau wrote: Tue Jan 16, 2018 2:31 am We want to get it all working first and moving to the 68030 is almost just a CPU swap in the schematics..... and who said I don't already have an Eagle schematic with the 68030RC50 :) ....
Yesssss!

Re: STE / MSTE 68020 booster

Posted: Thu Jan 25, 2018 12:44 am
by rpineau
So as expected.. we made a few mistakes on the v3 board, and by "we" I mean "I' :)
I messed up the footprint of a small SMD resistor array.. so of course the actual one don't fit (YC158 with a YC164 pad size ... RoRo .. Fired ! ).
We also made the PLCC plug SMD footprint a little bit tight. It fit but for the next version I increased the pad width to match the physical size (my fault there too)...
Juliusz is the one discovering these issue as he's assembling the board I sent him ..
So even when we're careful and do multiple review of the board between the 2 of us.. we still miss some stuff :).
These are not show stopper so we should be able to get the V3 working even with these issue (the TY158 are used as pull-ups on address pins, data pins and IRQ pins so we can work around this).
This probably mean a V4 will happen :)

Rodolphe