Looking for a 68060 with FPU & MMU

[NorthWay]

Motorola made significant changes with each new generation of 68K CPU

I know. I patched my own Exec years ago to properly detect the 060, fix its status, and set the flags for it.

So I didn't really see the need for having more than one version.

[SpeedGeek]

I know. I patched my own Exec years ago to properly detect the 060, fix its status, and set the flags for it.

So I didn't really see the need for having more than one version.

I wasn't aware that you (or anyone else) had previously patched exec for the 060. Otherwise, I certainly would have been willing to try yours. What version of exec is your patch based on?

If it's and older version than BB2 some users may still prefer a newer version.

[NorthWay]

What version of exec is your patch based on?

The original 3.1 of course. I was in a friendly race with Piru to come up with fixes and features for it. I don't think he incorporated my subroutine call twists, and I'm also a bit of a purist so I changed many macro and local calls to use the APIs.

Apart from the 060 stuff I think Piru has all the goodies you can wish for.

Ah, I found the code - nearly the last thing before the fpu testing (just 2 more instructions before it)

********
**
** Manually turn off MMU! Needs real mmu...
**
********
        moveq   #0,d1
        movec   d1,TC

        ;
        ; Do the 68060 test - PCR register does not exist on other CPUs
        ;
        bset    #AFB_68060,d0   ; guess at 060
cs_Test060
        movec   PCR,d1          ; flunks if 040 and clears the 060 bit
cs_Test060done
        btst    #AFB_68060,d0
        beq     cs_Not040

        and.l   #2,d1
        cmp.w   #2,d1
        beq     cs_Not040

        FNOP
        movec   d1,PCR          ; clear some odd bit

cs_Not040

[Cosmos Amiga]

@NorthWay

Again, we are at the first top lines of the exec.library... Zero system mounted...

Remember : the goal is to disable the Fpu with a 68000/010/020/030/040/EC/LC compatibility...

[SpeedGeek]

OK, as promised (to Cosmos) the first episode of A3660 overclocking has begun!

I attached a small cooling fan to the Rev. 1 CPU + Ramsey's CLK90 is modified for the A3000*.

Hopefully, as I acquire the additional components needed and time permitting clock speeds will increase with future episodes.

*Note: There is no practical overclocking limit with the adapter itself.      

[SpeedGeek]

OK, episode #2 of A3660 overclocking is completed!

This is the upper limit for this Rev. 1 CPU... Also, SDMAC is working at it's maximum CLK speed. I made a custom oscillator and added an extra 10 uF cap to the top PCB for this project.

Higher clock speeds are still possible but will require a late Rev. CPU and a custom timing hack to keep SDMAC happy....

[SpeedGeek]

OK, episode #3 of A3660 overclocking is completed!

Once again, many thanks to SuperCosmos for the rev. 6 060 (and for his patience with my stupid mistake delaying this update for another 2 months)
 
The custom oscillator I made used a dual frequency crystal so changing  the frequency was quite easy. The more complex part of this episode was  the CLK D4 GAL designed as the solution to keep SDMAC happy.

The CLK D4 GAL switches the mobo to a 1/4x clock during DMA so SDMAC is  supplied with clock speed it can handle and the mobo runs at the 1/2x  clock speed when the CPU masters the bus. See attached images.

This also works quite well with the 040 but I was really saving it for this episode!

Higher clock speeds are still possible but I will have to source some oscillators or crystals for the next episode.

[Cosmos Amiga]

Good luck !!

[SpeedGeek]

OK, episode #4 of A3660 overclocking is completed!

Unfortunately, SysSpeed becomes less accurate at higher clock speeds so I have included a Scout result as well.

The CLK_D4 GAL signal BGACK_040 is now connected to VCC. This always  runs the mobo at the 1/4x clock speed. Also, more A3000 mobo and CLK90  timing mods were made to keep the following clocks skew compensated and  stable:

68060 CPU = 80MHz
A3640 logic = 40MHz*
A3000 mobo = 20MHz

Note: Considering that the A3000 is a timing intolerant beast  overclocking the mobo to 40MHz was not a practical consideration here.

*A3640 state machine mod required

[Oldsmobile_Mike]

Note: Considering that the A3000 is a timing intolerant beast  overclocking the mobo to 40MHz was not a practical consideration here.

:laughing:


Beautiful work sir, as always!

Reminds me that one of these days I need to finish the speed hack you published a few years ago for the A2091.  I still have one, half done, sitting on a shelf.  Ugh!  

[Cosmos Amiga]

OK, episode #4 of A3660 overclocking is completed!

Unfortunately, SysSpeed becomes less accurate at higher clock speeds so I have included a Scout result as well.

The CLK_D4 GAL signal BGACK_040 is now connected to VCC. This always  runs the mobo at the 1/4x clock speed. Also, more A3000 mobo and CLK90  timing mods were made to keep the following clocks skew compensated and  stable:

68060 CPU = 80MHz
A3640 logic = 40MHz*
A3000 mobo = 20MHz

Note: Considering that the A3000 is a timing intolerant beast  overclocking the mobo to 40MHz was not a practical consideration here.

*A3640 state machine mod required

Fantastic !

Will works on the A4000 ?

[Jose]

Although I think that's awesome the 3640 doesn't have any memory, so it's of limited practical use.

[SpeedGeek]

Fantastic !

Will works on the A4000 ?

It should work with the A4000 but I don't have one to test it on. I would expect the A4000 to have more flexible timing options for CLK90 since I'm lucky to find one which keeps Ramsey and SDMAC working at non-standard clock speeds. :rolleyes: