68040 40Mhz Upgrade on Milan

All things related to the Hades and Milan clones

Moderators: Mug UK, moondog/.tSCc., [ProToS], lp, Moderator Team

medmed
Retro freak
Retro freak
Posts: 16
Joined: Sat Apr 02, 2011 5:06 am
Location: France, Paris

68040 40Mhz Upgrade on Milan

Postby medmed » Sat Aug 03, 2013 9:47 pm

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.
M.Medour - 1040STF, Mega STE + Spektrum card, Milan 040 + S3Video + ES1371.

rpineau
Captain Atari
Captain Atari
Posts: 493
Joined: Wed Jun 29, 2011 6:39 am
Location: California / USA
Contact:

Re: 68040 40Mhz Upgrade on Milan

Postby rpineau » Sat Aug 03, 2013 10:09 pm

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
Falcon + AB040 + Eclipse PCI + ATI Rage VGA card + NE2000 Ethernec + HxC Floppy Emulator
MegaSTE 4MB + CosmosEx / 1040 STF for hardware dev
http://www.rti-zone.org/atari.php

medmed
Retro freak
Retro freak
Posts: 16
Joined: Sat Apr 02, 2011 5:06 am
Location: France, Paris

Re: 68040 40Mhz Upgrade on Milan

Postby medmed » Sun Aug 04, 2013 12:09 am

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.
M.Medour - 1040STF, Mega STE + Spektrum card, Milan 040 + S3Video + ES1371.

Rustynutt
Captain Atari
Captain Atari
Posts: 234
Joined: Wed Mar 21, 2012 7:38 am
Location: Oregon
Contact:

Re: 68040 40Mhz Upgrade on Milan

Postby Rustynutt » Mon Oct 14, 2013 5:36 am

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
Captain Atari
Captain Atari
Posts: 234
Joined: Wed Mar 21, 2012 7:38 am
Location: Oregon
Contact:

Re: 68040 40Mhz Upgrade on Milan

Postby Rustynutt » Sat Jun 17, 2017 7:42 pm

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
Obsessive compulsive Atari behavior
Obsessive compulsive Atari behavior
Posts: 102
Joined: Fri Nov 09, 2007 1:53 pm
Location: England, GB

Re: 68040 40Mhz Upgrade on Milan

Postby PeterS » Sat Jul 08, 2017 12:16 pm

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
Captain Atari
Captain Atari
Posts: 234
Joined: Wed Mar 21, 2012 7:38 am
Location: Oregon
Contact:

Re: 68040 40Mhz Upgrade on Milan

Postby Rustynutt » Mon Jul 17, 2017 10:23 am

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
Obsessive compulsive Atari behavior
Obsessive compulsive Atari behavior
Posts: 102
Joined: Fri Nov 09, 2007 1:53 pm
Location: England, GB

Re: 68040 40Mhz Upgrade on Milan

Postby PeterS » Tue Jul 18, 2017 1:58 pm

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 ?

User avatar
rudis
Obsessive compulsive Atari behavior
Obsessive compulsive Atari behavior
Posts: 148
Joined: Mon Feb 14, 2011 9:41 am
Contact:

Re: 68040 40Mhz Upgrade on Milan

Postby rudis » Tue Jul 18, 2017 4:51 pm


PeterS
Obsessive compulsive Atari behavior
Obsessive compulsive Atari behavior
Posts: 102
Joined: Fri Nov 09, 2007 1:53 pm
Location: England, GB

Re: 68040 40Mhz Upgrade on Milan

Postby PeterS » Tue Jul 25, 2017 10:44 am

Another thought...

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


Social Media

     

Return to “Hades / Milan”

Who is online

Users browsing this forum: No registered users and 1 guest