V2.5 BOOSTER CURRENT PROTOTYPE STATUS

Help & information about the V2.5 booster.
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rpineau
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Re: V2.5 BOOSTER CURRENT PROTOTYPE STATUS

Post by rpineau » Fri Sep 08, 2017 7:24 pm

TOS 2.06 and up
but the TOS is only 256KB.
So you can totally be reading from one of the 256K block while programing another of these.
so with 1MB you can use half in read mode and half in write mode. That give you 2 x TOS
you then switch which one get accessed which switches (dip switches or jumper) and which one is being written.
So let's say you are running the first TOS, so it's in the first part of the flash. that means you can flash the 2nd part of the flash, which would be located in the last 256K block of the address space in write mode.
The flash would be organize like this :
[256K 1st TOS]
[256K 2nd TOS]

and you do the switching like when you have a dual TOS in an EPROM for the one that is being run and the one that is being written
We can figure our the logic equation for the select and /W.
so when running the 1st TOS you can flash the 2nd TOS. and if you need to reflash the 1st TOS you then need to be running the 2nd TOS (change it via a jumper or switch).
So you are always booting to $00E00000 but the CPLD + switch select the 1st or 2nd TOS.
Sn you are always writing to $00E80000, which the 2nd 512KB block and which TOS is being written is also selected by the CPLD based on which one is running for the read.

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exxos
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Re: V2.5 BOOSTER CURRENT PROTOTYPE STATUS

Post by exxos » Fri Sep 08, 2017 7:44 pm

ahh, ok I get what you mean now :)
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: V2.5 BOOSTER CURRENT PROTOTYPE STATUS

Post by exxos » Tue Sep 12, 2017 2:35 pm

So my new diodes just come, unfortunately they were so tiny, I think the scope probe tip was actually bigger than the diodes. So needless to say I gave up trying to solder them. :lol: note to self, check the size of the package before ordering. :roll:

So what I have done is to just simply try a 1N4148 diode and see what happens. I took some scope images before and after, though there was practically no difference between the two images.

NO DIODE
11-min.png
11-min.png (31.37 KiB) Viewed 701 times

WITH DIODE.
12-min.png
12-min.png (31.59 KiB) Viewed 700 times

While I did not see any clamping on the undershoot, the oscillation did seem a little smoother. This could be down to the self capacitance of the diode itself. As even the scope probe itself is enough to allow the machine to boot up. It actually seems rather stupid that such a small variation in signal quality can cause the machine to boot or not boot.


EDIT:

OK, I managed to solder stupidly tiny diode, results shown below.
IMG_1847.JPG
IMG_1847.JPG (86.42 KiB) Viewed 700 times

No diode.
b-min.png
b-min.png (30.21 KiB) Viewed 700 times

With diode.
c-min.png
c-min.png (28.92 KiB) Viewed 700 times

The undershoot without the diode is approximately 0.4V, with the diode approximately 0.25V, which is about what I expected from the datasheet.

I think overall just adding schmitt buffer to the PLD import and outputs on the 8 MHz clock should be okay to solve this problem. Actually I had to put a similar buffer on the STE booster because of PLD output problems. But obviously the PLD has input problems on the 8 MHz clock also, so buffer will be required. So likely no more updates until my small buffer PCBs arrive in a couple weeks time.
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: V2.5 BOOSTER CURRENT PROTOTYPE STATUS

Post by exxos » Thu Sep 14, 2017 9:58 pm

So I got a reply from ATMEL finally about this issue.At the moment they seem to be thinking it's a decoupling problem..

They actually suggested starting from the 16 MHz clock dividing it to 8 MHz internally in the PLD and using that as the 8 MHz source.Something which I did not actually think about before. Though the board now functions perfectly fine and is now cycling through gembench.

I am however, still not any further along as to why the undershoot on the motherboard 8 MHz clock is causing issues.but as it stands, the booster board seems to operate fine. So I still believe the PLD is somehow misbehaving when he sees the undershoot… The investigation continues…
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: V2.5 BOOSTER CURRENT PROTOTYPE STATUS

Post by exxos » Fri Sep 15, 2017 4:07 pm

Talking to Atmel We could only think that maybe the input clamp diodes on the PLD were causing the ground bounce to crash. Looking at the chart below…

clamp.JPG
clamp.JPG (66.52 KiB) Viewed 679 times
With 0.8 V undershoot, we could generate a 20 mA spike. So as a test I added several more capacitors onto the power pins of the PLD. This unfortunately did not make any difference. I am starting to think the problem isn't actually with the PLD at all.

Oddly connecting the scope probe to the 8 MHz motherboard side works exactly the same as connecting the scope to the PLD side, despite there being a 68R resistor between the two points. This makes me wonder if the lack of load on the 8 MHz signal is actually causing a bad clock to the glue IC.

So I have connected a 50pF capacitor to the 8 MHz clock motherboard side and it now boots up fine.

Without capacitor.
bbbbbbbb.png
bbbbbbbb.png (97.99 KiB) Viewed 679 times

With capacitor.
aaaaaaaa-min.png
aaaaaaaa-min.png (36.79 KiB) Viewed 679 times

So it seems, yet again, I have been chasing faults on the actual motherboard itself :roll:
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: V2.5 BOOSTER CURRENT PROTOTYPE STATUS

Post by exxos » Fri Sep 15, 2017 6:02 pm

32test.jpg
32test.jpg (145.45 KiB) Viewed 672 times
Looks very similar to before but now this is running of the 32 MHz oscillator not the one generated next to the shifter. This design is essentially what the mega ST uses.

It seems to work okay but am now seeing what seems to be the classic STFM video fault with the flickering black line at the top. It does not seem to be there all the time but I'm going to try my video fixes to see if I can eliminate it totally. Running GB6 and the flickering is not there anyway, which is odd.

32 MHz is now buffered as the motherboard one isn't strong enough to power anything but the shifter by itself. So decided just not to use that circuit and has put a standard 32 MHz oscillator on the booster board instead. This is buffered by the PLD, which is also very useful as I will also need 32 MHz inside the PLD the 32 MHz booster logic later on.

I uploaded of the video of the Flicker below.



Obviously this flicker was not there originally so I'm not sure why it is only showing up now.

Might as well add a cool crash screen in here as well..
crash.jpg
crash.jpg (130.2 KiB) Viewed 672 times
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: V2.5 BOOSTER CURRENT PROTOTYPE STATUS

Post by exxos » Fri Sep 15, 2017 6:37 pm

So this is my first 32 MHz test…
IMG_1858.JPG
IMG_1858.JPG (59.43 KiB) Viewed 670 times
I guess it did not do too well :lol:

So after a resync of /DTACK I now get this far…
IMG_1860.JPG
IMG_1860.JPG (35.23 KiB) Viewed 670 times
I had similar issues to this with the STE booster, it needs a buffer on the CPU clock, and I am still waiting for the PCBs to arrive for that bit :roll:

But in any case, it is a huge step to finally get progress towards 32 MHz on the STF and working :D
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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rpineau
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Re: V2.5 BOOSTER CURRENT PROTOTYPE STATUS

Post by rpineau » Fri Sep 15, 2017 7:26 pm

Nice work.

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Re: V2.5 BOOSTER CURRENT PROTOTYPE STATUS

Post by exxos » Sun Sep 24, 2017 10:19 pm

My little buffer boards came over the weekend :) not sure when I will get chance to try these hopefully in a few days :)

IMG_1873.JPG
IMG_1873.JPG (53.24 KiB) Viewed 447 times
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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Re: V2.5 BOOSTER CURRENT PROTOTYPE STATUS

Post by exxos » Tue Dec 12, 2017 10:56 pm

Still not had time to work on this yet :(

But in light of TerribleFire using a PLL to x4 the 8mhz clock to 32mhz.. I am going to try this.. As it would save a lot of work in not having to jiggle with the shifters 32mhz circuit..

I did try a PLL way back in 2013, but it was always out of sync.. so gave up. but TF mentioned it was a clone of another chip, which gave proper specs.. long story short.. it sucked.. but theres a similar IC (which TF is using) which doesn't suck..

So I've quickly designed this board..

a1902f867bf8a4d5fbdb0f3cf755db37.png
a1902f867bf8a4d5fbdb0f3cf755db37.png (78.59 KiB) Viewed 163 times

Where I can plug into my osc socket on my booster, which I can wire in 8mhz and output 16mhz or 32mhz.. This will hopefully allow me to skip all the odd video issues.. but I am still going to investigate that anyway when I get time.. but main point is that 32mhz fitting will be a whole lot less work on a production board... Likely will get back to this in the new year (hopefully).
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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