68040 40Mhz Upgrade on Milan

[medmed]

Hi,

I have a 68040 who can run at 40Mhz and a Milan with a 68040 clocked to 25Mhz.

I'm thinking to swap the original cpu by the 40Mhz but i've read the following warning from this link: http://www.der-ingo.de/en/milanhelp/hardware.html

If you want to run you Milan with more than 25 MHz properly, you'll need one very special chip, which is very hard to find. It is the chip 74ACT157 SO16, small version

I've searched what this IC do (found this link http://www.fairchildsemi.com/ds/74/74ACT157.pdf) but i already don't understand why we need this to change the clock of a cpu.

If someone can help me and sorry for my bad english.

Many thanks.

[rpineau]

It's a component response time issue. If you increase the frequency, the component need to react at least as fast as a clock cycle, sometimes faster.
The 74ACTxxx family as a response time of 7.5 to 9.5 ns.
If you can't find them I'll recommend the 74FCT157 as it has a response time of 4.3 ns at 5v which is even faster than the 74ACT157.
the 74FTC157 in SOIC-16 package is easy to find (mouser is a good source if you're in USA) and is cheap ( mouser has it for $1.72).

Regards,
Rodolphe

[medmed]

I hoped to make my milan more powerful without make the 060 adapter by just replacing the 040.

It seems that to make the milan most powerful we can't pass through.

I'll see with the shematics on the web and I think I'll reopen new topic to understand what I do

Thank you very much.

[Rustynutt]

When working on the Milan, it is easy to forget to power off before swapping keyboard connector.
This scared me one night! Reading about other motherboards helped me trace down a problem I had when the keyboard stopped working.
From the keyboard connector to the control chip, there is a place where the trace where it makes a tight turn. The material is very very thin at that point, and swapping the keyboard out with power to the board can cause this to burn easily. Very small amperage, I repaired the trace, installing a fuze would be the best protection.

My Milan is boxed up ATM, if anyone has this problem, or wishes to put information into their note book, will take time to locate the circuit.

Good luck replacing the slower chips. This is a project I wish to do as well in the future. I have clocked my Milan at 33MHz, but no faster. It is much more stable at 25MHz, which is a waste of a good machine .

[Rustynutt]

Has anyone replaced the IC and have had success running the Milan bus at higher speeds than they were before? When I get my Milan back from Rodolphe that's one of the first improvements I'll do. About 2 years ago on Amibay, a user had a PCB kit made the same as the original one sold with the Milan. Purchased 3. They require some hours soldering the 040 to 060 sockets and SMT components. Took me a few long evenings to finish one kit, I'm a slow soldier ! When it arrives, hoping it smooth sailing to 06O world. The other kit will be used on an Afterburner, using Jo Even's idea of burning EmuTos on to cartridge ROM to remove TOS 4.04 from the compatibility equation.

[PeterS]

Many years ago I wrote an Article for Atari Computing mag on my upgrade experience from 040 to 060. You can probably still find it online.

My Milan will work at 30/60MHz but the scsi causes it to crash so I have to run at 25/50MHz.

If there is a clock chip upgrade that would increase the usable clock options I would be interested in getting it done. My solder skills probably aren't up to it.

[Rustynutt]

Have been experimenting with the MC88LV926.
These can be chained together for distribution of signal.
I think if you are using a 25MHz bus, should be possible to take the 2x clock from the chained IC to provide 100MHz to the 060. Maybe if the 060 cannot operate at 100MHz, setting the Milan bus to 20MHz would run the 060 at 80MHz. Soon will be testing this idea on my Milan. The 060 adapter for the Milan uses an F157 for the required reset delay of the 060. It's not a very nice way to control the timing, IMHO, depending on a propagation delay. The MC88LV926 is designed for this purpose, with added benefits for the system.
The CT6xx use this IC, as does an Apple 50MHz 68040 DiiMO Cache accelerator card for my Quadra 840
But to use with the Milan 060 adapter, as Rodolphe Czuba would say, "with solders"


http://www.exxoshost.co.uk/atari/mirror ... an060.htm5
Memories

[PeterS]

I do remember seeing that the 68060 can run at 4x bus speed so 20/80MHz would be achievable, although would it be any faster in the real world than 25/50 ?

[rudis]

http://www.exxoshost.co.uk/atari/mirror ... an060.htm5
Memories

The Link doesnt work. Remove the 5.
http://www.exxoshost.co.uk/atari/mirror ... lan060.htm

[PeterS]

Another thought...

Could a Coldfire adapter be made to replace the 060 adapter ? Patch the bootblock/TOS and the Milan joins the Firebee.

[joska]

Could a Coldfire adapter be made to replace the 060 adapter ? Patch the bootblock/TOS and the Milan joins the Firebee.

I can't see a single good thing about that. Incompatible CPU and slow RAM

[PeterS]

http://www.exxoshost.co.uk/atari/mirror ... lan060.htm

The chip is on the 68060 adapter board so getting at it is not as difficult as a chip on the motherboard.

I was told scsi doesn't work because of the motherboard revision, I mainly run at 25Mhz. It would be nice to be able to have an external switch to change speeds but I don't know if adding wires and a switch to the jumper block will work.

[shoggoth]

I used a 060 upgrade adapter intended for the Amiga ti upgrade my Milan -> 060. Gives quite a bit more oomph.

[Neurotoxic]

I used a 060 upgrade adapter intended for the Amiga ti upgrade my Milan -> 060. Gives quite a bit more oomph.

Wich adapter did you use? Do you have any link to a website? I also want to upgrade my Milan with a 68060 cpu but I don't know where to get the correct adapter. Did you have to modify your adapter or could you use it right out of the box?

[Rustynutt]

The Amiga 060 adapters I have were a kit a user on Amibay sold a few years ago. I don't think he had made more than ordered by other users, look for the thread in the Amibay forum.

[Neurotoxic]

Thanks for your information. Unfortunately my not there registered there but I will have a look. And you could use the adapter right out of the box or did you had to do any modifications?

[shoggoth]

Thanks for your information. Unfortunately my not there registered there but I will have a look. And you could use the adapter right out of the box or did you had to do any modifications?

No modifications whatsoever. The adapter doesn't do much, it doesn't contain any logic etc. It was produced fairly recently afaik.

[Rustynutt]

Like Shoggoth says, it's a simple adapter. Mine were not assembled, soldering required. May have been more recent ones available.

[Neurotoxic]

Thanks for your information. Unfortunately my not there registered there but I will have a look. And you could use the adapter right out of the box or did you had to do any modifications?

No modifications whatsoever. The adapter doesn't do much, it doesn't contain any logic etc. It was produced fairly recently afaik.

Like Shoggoth says, it's a simple adapter. Mine were not assembled, soldering required. May have been more recent ones available.

I just had a look on ebay and I found this adapter including a 68060 CPU:

https://www.ebay.de/itm/Commodore-Amiga-68060-CPU-Adapter-professionally-builti-ncluding-Rev6-CPU/172987389957?hash=item2846da1805:g:W-kAAOSwsFpaEFuo

Might that work, too? It's only a little bit expensive. Perhaps I'm going to ask my friends if they would like to give the adapter to me as a christmas present.

[Rustynutt]

Thanks for your information. Unfortunately my not there registered there but I will have a look. And you could use the adapter right out of the box or did you had to do any modifications?

No modifications whatsoever. The adapter doesn't do much, it doesn't contain any logic etc. It was produced fairly recently afaik.

Like Shoggoth says, it's a simple adapter. Mine were not assembled, soldering required. May have been more recent ones available.

I just had a look on ebay and I found this adapter including a 68060 CPU:

https://www.ebay.de/itm/Commodore-Amiga-68060-CPU-Adapter-professionally-builti-ncluding-Rev6-CPU/172987389957?hash=item2846da1805:g:W-kAAOSwsFpaEFuo

Might that work, too? It's only a little bit expensive. Perhaps I'm going to ask my friends if they would like to give the adapter to me as a christmas present.

Finally got to a box that has the adapter kits I purchased. Have one spare, are you still interested/looking?

[PeterS]

The 060 adapter for the Milan uses an F157 for the required reset delay of the 060.

https://www.mouser.co.uk/Search/Refine. ... d=74fct157

There seems to be quite a few "versions" in the SO16 package.

[Rustynutt]

Cool, solder iron will stay warm after getting a Falcon out the door.

[PeterS]

I had a look at the 060 adapter in my Milan. Hard to read but the ic is a 74F157AD.

[Rustynutt]

Having fricking CT063 problems now. Worked perfectly 8 months ago. Its now giving me fits, can't trouble shoot until it boots. I'll order the SO16.
Could you write a blurb about the order of installing the 060 files on the Milan.

Also, now have a programmer to update thd board. With all things, it's old an not sure it's ever been flashed.

[PeterS]

It's been a very long time since I flashed the rom.

I do know it will boot the 040 even if it has been flashed with the 060 version. I was able to do a lot of tests switching cpu's without having to re-flash all the time.