exxos's Atari, Amiga & retro forum

@leonk While I did post a screenshot of the SDMA (this is measured at the SDMA end! not the clock patch end) I did not post a picture of my original signal without clock patch. All I can say is the original is absolutely atrocious, the V2 is a massive improvement, V4 is creme-de-la-creme. But like I say, V4 for non-bus-boosted Falcons, V2 for bus-boosted (because it includes the Phantom-like delay buffer)

Steve wrote: 06 Jul 2024 11:11

Please see my comments in this post: viewtopic.php?p=115904#p115904
V4 is not suitable for bus boosted Falcons, I've extensively tested it. But it is possibly the best for non-bus boosted Falcons. If there was another clockpatch for you to try on bus-boost, it would be the V2 (Because the V2 includes the Phantom-like delay buffer, V4 does not)

Thanks for your reply. Just to be sure, as I have a CT60e, does it still count as a non-bus boosted falcon? I'm not familiar with all this Phantom-like delay buffer and similar.

Bus boost is nothing to do with a CPU upgrade. So you should be fine with V4.

ok, thanks!

exxos wrote: 06 Jul 2024 10:31 Maybe @Badwolf can scope his falcons sdma clock (on the sdma pin itself) next time he has his falcon connected up to see what he gets on X1 and X10.

Looks pretty crusty.

SMDA PIN 110:

But that said, it's a fairly good representation of the source:

Interestingly the x1 probe doesn't look much different. Smoothed out because of the extra capacitance, I imagine.

Zero level is excellent throughout.


I think I have a v2 and haven't applied any other patches (pull down or inline termination) to the SDMA. I don't have an FPU on board.

BW

Badwolf wrote: 06 Jul 2024 15:00 I think I have a v2 and haven't applied any other patches (pull down or inline termination) to the SDMA. I don't have an FPU on board.

Yeah the V2 had mods done over the years.

BTW is your scope a 1052 like mine ?

@exxos
I have a small question: earlier in this thread, you mention this:

"The original Atari F04 "hack" and only something like 3V logic high drive."

But on the installation page of the V2/3 and V4, in the part"THE FINAL FALCON CLOCK PATCH INVESTIGATION 2022", you mention this:

What we see here is a overshoot of over 8 volts (should be 5volts) and a undershoot of almost 3Volts. This can indeed be extremely damaging to connected chips.

Doest that mean that we have with the Atari / regular common clock patch available a pic at 8 volts and then the high signal come quickly back to 3V?

In other words, are the regular common clock patches giving too much voltage in overshoot where an unmodified machine won't? If yes, this would mean that in fact, the others clock patches are not good for the chips in the machine?

Thanks for helping me understand this complex topic :-)

I suggest readup on undershoot and overshoot to understand it all better.
https://en.m.wikipedia.org/wiki/Overshoot_(signal)

Also how bad grounding can make problems worse.

Indeed the generic patches don't have any sort of termination and cause spikes in voltages as I've shown which isn't a good thing. Most general clock patches that I've seen are just clones of the generic Atari design. Aside from being a neater install, they dont don't offer anything different. I did a lot of research into the issues and built my patches based on all the faults and problems i have seen. There are also other designs such as what nemesis and line audio etc did. But I personally consider all those designs obsolete these days as they haven't been updated in over 30 years now.

ok, thanks. So, better stay away from others regular patch.

Swissfalcon wrote: 07 Jul 2024 16:31 ok, thanks. So, better stay away from others regular patch.

Yes. They have a lot of known problems which is why I spent considerable time investigating issues people were having. A lot couldn't reliability run ACE tracker for example.