TF1260 100Mhz 060 Rev 4 o'clock woes solved with PHASE

[ManuelAndre123]

Hi.

Like me, most of you TF1260 owners have tried to overclock their 060 CPU (LC or not) to 100Mhz with the command cpuspeed SPEED 100 and succeeded until they tried the game "Fears", the CD 32 version (or even the normal AGA version) and the system went BOOM (locked, crashed) even if SysInfo passed with 75K+ score and AIBB also passed without any errors at 100Mhz with this default "Clock Phase 2". (~75Mhz to ~83 range is highly unstable)

So what's the deal? When using the cpuspeed SPEED 100 command without any further parameters its "Clock Phase" defaults to 2.

What the hell is this clock phase?

I don't know. But if you change it to 0, so cpuspeed SPEED 100 PHASE 0, you get 100Mhz speed with 0 as "clock phase" AND now comes the bonus...
The system remains rock steady whatever you throw at it!

Does anyone has knowledge about this PHASE parameter since it does not seem to interfere with any other parts of the system, benchmarks etc...???

Thank you!

[terriblefire]

it's a parameter used to advance or retard the 14mhz clock in relation to the full speed clock

[ManuelAndre123]

And I was thinking these speed issues were solved AND this does not explain (or you are not explaining) what the correlation is bewteen the SPEED and its PHASE parameters.

Please elaborate why one combination works or why not.

Thank you.

[terriblefire]

And I was thinking these speed issues were solved AND this does not explain (or you are not explaining) what the correlation is bewteen the SPEED and its PHASE parameters.

Please elaborate why one combination works or why not.

Thank you.

There is no relation between SPEED and PHASE. They control different things.

SPEED sets the clock speed.

There is a 14Mhz clock regenerated by sampling the amiga clock using the cpu clock speed. This clock is in the same clock domain (edges are aligned) as the cpu so they can be used without incurring a 2 clock penalty (I am not going to explain clock domains its a massive subject area). When this clock is recreated it needs to be advanced or retarded so that the edges line up so that it works. The value that works is found more less by trial and error. Some systems need a tweak. I've used the values that were reported to me as working during a major 4 week testing period with 10+ folk and every A1200 motherboard revision i could get my hands on. The parameter is left there for the edge case systems that need a little extra tuning.

[ManuelAndre123]

OK, so it can be helpful in some cases like mine and possibly others.

Trial and error (and avoid ~75 - ~83Mhz frequencies)

Good to know.

Thank you!

[terriblefire]

OK, so it can be helpful in some cases like mine and possibly others.

Trial and error (and avoid ~75 - ~83Mhz frequencies)

Good to know.

Thank you!

75 is documented as "works for some". 83 works fine for me but nobody else it seems. 94 seems the most stable.

[ManuelAndre123]

And I was thinking these speed issues were solved AND this does not explain (or you are not explaining) what the correlation is bewteen the SPEED and its PHASE parameters.

Please elaborate why one combination works or why not.

Thank you.

There is no relation between SPEED and PHASE. They control different things.

SPEED sets the clock speed.

There is a 14Mhz clock regenerated by sampling the amiga clock using the cpu clock speed. This clock is in the same clock domain (edges are aligned) as the cpu so they can be used without incurring a 2 clock penalty (I am not going to explain clock domains its a massive subject area). When this clock is recreated it needs to be advanced or retarded so that the edges line up so that it works. The value that works is found more less by trial and error. Some systems need a tweak. I've used the values that were reported to me as working during a major 4 week testing period with 10+ folk and every A1200 motherboard revision i could get my hands on. The parameter is left there for the edge case systems that need a little extra tuning.

This thing keeps me bugging.
If the PHASE parameter can make or break a system, what does the other optional cpuspeed CRYSTAL parameter do?

And why are these extra params NOT explained or mentioned in John "Chucky" Hertell's TF1260 page?
Chucky's TF1260 Information

Thank you!

[terriblefire]

And why are these extra params NOT explained or mentioned in John "Chucky" Hertell's TF1260 page?
Chucky's TF1260 Information

You're pretty much the first person to need to use it. This isnt a commercial product, i dont get paid for these cards at all, so i havent got much interest in documenting a feature that almost nobody uses. infact in a perfect world the phase parameter would not be need.

You arent guaranteed anything over 50Mhz. Everyone who was sold a TF1260 by a builder (one with a logo) had 30 days to return the card if they didnt like it. Anyone with a card without a logo i dont support at all.

[ManuelAndre123]

And why are these extra params NOT explained or mentioned in John "Chucky" Hertell's TF1260 page?
Chucky's TF1260 Information

You're pretty much the first person to need to use it. This isnt a commercial product, i dont get paid for these cards at all, so i havent got much interest in documenting a feature that almost nobody uses. infact in a perfect world the phase parameter would not be need.

You arent guaranteed anything over 50Mhz. Everyone who was sold a TF1260 by a builder (one with a logo) had 30 days to return the card if they didnt like it. Anyone with a card without a logo i dont support at all.

There is always a first ;)

I should have mentioned it before anything else but I'm on version 1000 of the firmware, so not the latest 68090 one, and the LC060 CPU has the Freescale logo instead of the Motorola one. So I'm kinda lucky CPU-wise since it is probably one of the latest production masks and manufacturing process (0.42 μm if I'm correct).

The card was delivered by amigastore.eu and I bought it the 2nd of october 2023.

What the hell! I should have version 68090 (date 2023_05_19) of the firmware instead of 1000!

From what I've seen, with the 68090 FW, some essential timings were corrected/changed whan accessing CHIP-ram? (or NOT when on version 1000?)

Again, tahnk you for enduring my "out of the ordinary" questions.

[terriblefire]

Give it a rest with the phase parameter already. it works different on every fw version. it's an internal tuning parameter and it's not supposed to be public.

I reserve the right to completely change it in the next fw version