PAK030 40MHz & STorm ST issues

[Darklord]

So...a powerhouse 50mhz machine with *no* 68882 FPU,

Or

A powerhouse 40mhz machine with a 688882 FPU?

I know which way I'm leaning considering that there's very little
software that takes advantage of the FPU and IIRC, it's even
worse with the 68882 as it's incompatible with some 68881
friendly software.

What does everyone else think? Thanks.

[Badwolf]

So...a powerhouse 50mhz machine with *no* 68882 FPU,

Or

A powerhouse 40mhz machine with a 688882 FPU?
...
What does everyone else think? Thanks.

I'd go 40 + FPU personally.

Because the most common MiNT compiler toolchain presupposes an FPU for all the 020-060 target it makes life a little easier there, although that's entirely work-aroundable by using the 000-builds or by using Anders' FPU emulation software these days. When you have something that will use the FPU, it's a nice to have.

+ I suspect you won't notice the 10MHz difference and the heat saving will be considerable.

Mind you, I'm not familiar with the PAK030 board. would it be possible to downrate the FPU like I do in the stock DFB1 build?

BW

[frank.lukas]

... if such an FPU is reprinted use Acetone to remove the printing. Original prints cannot be removed with Acetone.

I have two PAK68/3-030 50Mhz running with PGA MC68882-50 and all works fine ...

Fake or not Fake FPUs -> https://68kmla.org/bb/index.php?threads ... ata.46717/

DML FPU Test -> https://www.atari-forum.com/viewtopic.php?t=30671
GEMBENCH FPU test run fine without errors but the FPU is faulty and works not right.

[Darklord]

... if such an FPU is reprinted use Acetone to remove the printing. Original prints cannot be removed with Acetone.

I have two PAK68/3-030 50Mhz running with PGA MC68882-50 and all works fine ...

Fake or not Fake FPUs -> https://68kmla.org/bb/index.php?threads ... ata.46717/

DML FPU Test -> https://www.atari-forum.com/viewtopic.php?t=30671
GEMBENCH FPU test run fine without errors but the FPU is faulty and works not right.

I'm glad your Pak boards work fine - it seems that most do!

I'll look at that guide and try to match it with the three 68882's I have, thanks.

Doug Little's FPU Test software is what I've been using. It passes at 40mhz and fails (6-7 bombs!) at 50mhz.

[Darklord]

I'd go 40 + FPU personally.

Because the most common MiNT compiler toolchain presupposes an FPU for all the 020-060 target it makes life a little easier there, although that's entirely work-aroundable by using the 000-builds or by using Anders' FPU emulation software these days. When you have something that will use the FPU, it's a nice to have.

+ I suspect you won't notice the 10MHz difference and the heat saving will be considerable.

Mind you, I'm not familiar with the PAK030 board. would it be possible to downrate the FPU like I do in the stock DFB1 build?

BW

You're probably right about that extra 10mhz.

My understanding is (and someone correct me if I'm wrong) that the oscillator controls both the 68030
and the 68882. IIRC, the Pak document says it's best to have both chips rated at the same speed. In my
case, both of mine are rated for 50mhz. I can put an oscillator in of 32, 40, and 50mhz speeds and it
works, except for the 50mhz FPU problem I've mentioned.

I don't have any lower rated 68030's or 68882's to try (just for the fun of it)...

Thanks.

[Darklord]

So I attempted to use the guide Frank posted, matching it up to the
3 FPU's I have (I posted a picture of them on Page 2 of this thread).

It looks like they are from the 19th week of 1990, the 36th week of 1990,
and the 24th week of 1992.

I'd appreciate it if someone could double-check me but it looks to me
as if they are valid FPU's?

Thanks all.

[Badwolf]

Mind you, I'm not familiar with the PAK030 board. would it be possible to downrate the FPU like I do in the stock DFB1 build?

My understanding is (and someone correct me if I'm wrong) that the oscillator controls both the 68030
and the 68882.
[/quote]

Ah, yes, I thought so. But it may be possible to hack in a separate oscillator or a flipflop to half the oscillator to the FPU?

They don't have to run at the same clock rate, but I've found they work best when they're within a factor of two of each other.

In my original DFB1 I have one 50MHz oscillator for the CPU and one 40MHz oscillator for the FPU.

BW

[frank.lukas]

I think on the PAK68/3 there a a three pin jumper so you can select FPU Clock = CPU Clock on one side or on the other side fix 16Mhz ...

You can put your extra spezial FPU Clock on the middle Pin ...


But the manual say do not run the FPU slower than the CPU Clock are !!!