STE V1.5 32MHz BOOSTER - STATUS

Help & information about the STE V1 booster.
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rpineau
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Re: STE V1.5 32MHz BOOSTER - STATUS

Post by rpineau » Fri Apr 13, 2018 2:31 am

Ok, then next thing that comes to mind is to not use /AS to validate so that you can assert /OE as soon as the address match the TOS :)

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exxos
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Re: STE V1.5 32MHz BOOSTER - STATUS

Post by exxos » Fri Apr 13, 2018 12:59 pm

rpineau wrote:
Fri Apr 13, 2018 2:31 am
Ok, then next thing that comes to mind is to not use /AS to validate so that you can assert /OE as soon as the address match the TOS :)
Nope :)

This is original ROM access...
r2.png
r2.png (4.74 KiB) Viewed 416 times

And with the predictive ROM read technology..
r1.png
r1.png (4.6 KiB) Viewed 416 times

This actually gives me a idea.. That possibly I could just run the CPU at 40 MHz all the time, and only switch down to 8Mhz when doing 6800 cycles..
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

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Re: STE V1.5 32MHz BOOSTER - STATUS

Post by exxos » Fri Apr 13, 2018 2:25 pm

It seems fate is telling me it is time to do a new PCB.. :roll:

Snapping the DTACK pin of the CPU probably did not help much :lol: even after trying to tack it back on I just keep getting bombs. When it did work, machine ran 50% slower :roll:

cs.jpg
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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

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Re: STE V1.5 32MHz BOOSTER - STATUS

Post by exxos » Fri Apr 13, 2018 3:56 pm

New PCB layout :)

A few mods and tweaks here and there. Added in a 3.3V regulator and oscillator. Done the DTACK routing via the GAL. Also rooted VMA, VPA just in case I want to experiment later.

I use a small schmitt buffer to clean up the GAL output to the CPU clock. One thing I have not been able to figure out is that it only works with a 220R resistor from the GAL output to the buffer input. The output of the buffer exactly the same regardless of resistor use. But any other value and machine refuses to boot. The only difference is that the resistor lessens the voltage to the input of the buffer.. So no idea what is going on there.

I found a different buffer it is not a schmitt one, I do not think this is really needed anyway, but the new buffer does not register a logic one until about 3.8V. The GAL output does have a small glitch, so this gives a huge hysteresis voltage which should act better than a schmitt buffer in this case.

Also done some minor PCB rerouting in a few places. So now this board is ready to order I think, so I will likely order it next week. Then it's back to waiting for PCBs to arrive again :roll:

REVD.jpg
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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

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Re: STE V1.5 32MHz BOOSTER - STATUS

Post by exxos » Mon Apr 23, 2018 1:37 pm

Still waiting for the PCBs.. But the plastic squares just arrived...

stesq.jpg
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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

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troed
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Re: STE V1.5 32MHz BOOSTER - STATUS

Post by troed » Mon Apr 23, 2018 2:02 pm

What's the dimension and needed tolerance of those squares? You're saying that they're really expensive ..

3D printers have very different capabilities depending on how much you spend on them. The one I have (Ultimaker 2) has very good tolerance levels. The first layer gets a bit squished and needs to be filed down but otherwise I've been very happy with what I've printed.
With PLA, which has a substantially smaller shrink effect while cooling down, I got positioning accuracies down to 0.1mm on nearly any dimension, coming mainly from the play of the belts. However, bores will always be up to half a millimeter smaller in diameter than they should and outer contours 0.1-0.2mm larger.

It's nearly impossible to predict. Or it would require a software similar to the software used for tool design in injection moulding. The usual way to go is try and error. Print the part once, measure the important dimensions and adjust the model, print again etc.
https://community.ultimaker.com/topic/5 ... of-prints/

I'd be happy to spend a few hours on seeing if I can get the tolerance level needed (I assume I only have to check for a snug fit in a PLCC68 socket?) if it's a substantial cost saving for you. Unless you already ordered all the plastic you needed .. :)

/Troed

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Re: STE V1.5 32MHz BOOSTER - STATUS

Post by exxos » Mon Apr 23, 2018 2:14 pm

troed wrote:
Mon Apr 23, 2018 2:02 pm
I'd be happy to spend a few hours on seeing if I can get the tolerance level needed (I assume I only have to check for a snug fit in a PLCC68 socket?) if it's a substantial cost saving for you. Unless you already ordered all the plastic you needed .. :)
These squares are costing about £7 each at the moment and I got five of them made with a precision engineering company in the UK.

I did consider 3-D printing them, something I just don't have the time to mess about with... Course of no objection if you want to try :)

These are 24.40mm square, 5mm thick, with a 5 mm rounded corner.. Basically it's just got to fit snug in the socket like the CPU does. Problem is too small and it won't hold the pins on the socket, too large and it physically wont fit.
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

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troed
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Re: STE V1.5 32MHz BOOSTER - STATUS

Post by troed » Mon Apr 23, 2018 2:18 pm

exxos wrote:
Mon Apr 23, 2018 2:14 pm
These are 24.40mm square, 5mm thick, with a 5 mm rounded corner.. Basically it's just got to fit snug in the socket like the CPU does. Problem is too small and it won't hold the pins on the socket, too large and it physically wont fit.
Perfect - I'll try to get something done this week. I need to do at least _some_ printing every now and then to justify the cost of the printer ;)

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Re: STE V1.5 32MHz BOOSTER - STATUS

Post by rubber_jonnie » Mon Apr 23, 2018 3:47 pm

So the idea would be that it ends up like a hand assembled version of this:
R244686-01.jpg
R244686-01.jpg (41.53 KiB) Viewed 239 times
Will the idea be that the plastic square will be fixed to the PCB?
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Re: STE V1.5 32MHz BOOSTER - STATUS

Post by exxos » Mon Apr 23, 2018 4:11 pm

rubber_jonnie wrote:
Mon Apr 23, 2018 3:47 pm
So the idea would be that it ends up like a hand assembled version of this:
Yes and no.. If you look at the images in previous posts you can see how it plugs in.. The only issue is this a bit wobbly as nothing to hold the pins in place inside the socket.. It is a pretty tight fit, but need some sort of pressure on the pins to make sure they contact under a little bit of pressure.
rubber_jonnie wrote:
Mon Apr 23, 2018 3:47 pm
Will the idea be that the plastic square will be fixed to the PCB?
Likely not.. We talking factions of a millimetre tolerance , it would be near impossible to do that I think.

The pins on the booster go on the outside of the pins in the socket, those PLCC plugs connect on the inside of the pins just like the CPU does. This is a better idea and method in general, but I cannot do this because I need to solder the CPU onto the PCB and the pins would be pretty much underneath the CPU pins, so be basically impossible to solder together . Not only that, some of the signals are broken and run via the GAL, so I cannot have the CPU directly on top of the pins.. The only methods to solve this is to move the pins away from the CPU, which means the pins push into the outside of the socket on the motherboard...

This is exactly how the 4MB RAM board I also sell works... There is a image which shows it better....

Image

The idea does work, but it is more of a bugger to fit than the proper PLCC plugs. The MMU DRAM board fits in pretty easily as there is only 3 rows of pins, but in this case there is 4 rows, and it is lot more difficult to fit. Though I am thinking of soldering the pins on the bottom side of the PCB making them shorter and hopefully less likely to bend about while trying to insert it.. I have seen this done before on some other Marpet RAM upgrades.. Of course soldering the pins in the first place and keeping them perfectly straight is also a bit of a challenge in itself..

In any case, as there is no CPU in the socket, I use the plastic square is instead to hold it all together and in place.. Of course with the DRAM board, the MMU itself does that job..
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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