TerribleFire/Stephen,
I'm hoping you take this serious as I think this has a high probability of being useful to you (not just me). I also very much desire success of this project and hope to make this my go-to card. Please fully read to understand what I'm saying as there is some nuance. (And thank you for all the hard work!)
I have a modded-per-your-instructions 1200 (caps, edge connector, etc.). It is dead stable w/my ACA 68030 card and my Blizzard PPC+060 card. This is despite it being quite expanded. This is my main 1200, used nearly daily.
The original firmware on the TF worked for 80% of what I do, but the other 20% is clearly being addressed in the newest alpha. (THANK YOU!)
To my main point:
In the original firmware (80% useful for me) I HAD to use a custom pre-computed phase value in my heavily expanded 1200. Doing so allowed me to run STABLE at 80MHz (or any other speed below that). The default values ALWAYS caused immediate lockups except for at 50MHz where it "just squeaked by" for the 80% I could do on the TF at that time.
In the alpha (100% useful for me IF I can address this), the phase value for 50MHz is similarly marginal on my machine, however the new tool prevents me from using phase values beyond the first few values. So I cannot set the phase for what I need. Speeds > 50MHz on the alpha cause the same lockups I would receive from the default phase values on the original firmware.
I believe this phase stuff may be a clue to some issues people's experience. I can tell you the #1 core problem for me is the timing and complexity of using an Elbox Fast ATA IV controller -- or at least the way I'm using it -- with a fast modern SATA SSD (via adapter). It is heavily DMA'd and adds quite a lot of tightness to the bus access timings.
In short, are weirdo phase values possible on alpha if the tool is unlocked? This is a serious question and I'm genuinely trying to help both of us.
For reference, here's the phase value calculation I used on original firmware. I derived this from my own analysis:
round(<Desired MHz>/(28.636363/4)) ... for convenience I just use round(<Desired MHz>/7.16)
This yields the following phase values:
50 MHz = 7
63 MHz = 9
75 MHz = 10
80 MHz = 11
All of those were completely stable for me on original firmware and were a requirement for stability for me.
Note my 060 is a Rev6, but the same values applied for my Rev 5 though it could not run at 80.
My reasoning for the weird values was that clocks are continuous and this allowed for effectively "half clocks". As I figured out the values, I found it very telling that they aligned to what is effectively a skew of the base amiga frequencies. I don't know if the TF's clock is routed through a CPLD or not but I suspect a phase alignment issue or possibly inversion (high vs low and/or rising edge vs falling edge) vs the motherboard's clock. Once again, I'm just trying to throw out my thoughts not as any kind of fact but rather as a possibility. My goal is to help the project.
Anyway, I'd like to help and also ask if an unlocked cpuspeed tool for alpha is available.
I am an old heavy overclocker and tinker in building electronics (I have a scope too) so I'm basing a lot of this on a "sixth sense" of what I suspect is happening. I admit that's not scientific though.
Also, feel free to PM if that's preferred for whatever reason.
Appreciated,
Greg