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Cloning the Interware Booster 30

mg.man

Well-known member
As mentioned in the "Cloning the MicroMac MMXL99 LC-LCII-CC" thread... I have just picked up one of these little beauties, which seems to have one of the more crack-able GALs:

20220401_154903.jpg

20220401_154929.jpg

There's not much info out there on the 'web about it... @max1zzz, @Bolle, have either of you looked into cloning one of these before?
 

Bolle

Well-known member
Have yet to see an Interware card that has GALs that are actually locked. No cracking needed, pretty sure you'll be able to just read it.
 

Trash80toHP_Mini

NIGHT STALKER
Things are getting very exciting around here, a (two?) simple LC accelerator and my simple SE accelerator dumped into max's lap at once.

#1 tangent: not ready to reboot the Performer thread quite yet. :p @Bolle have you had a chance to try my Performer in an SE on Killy Klip. That one might just replace the 68000 on a socket, will that work? Have you got enough done with it to send it along to max? I know you're busy as a one armed paper hanger for quite some time. ;)
 

Franklinstein

Well-known member
Yeah that Moto chip basically is there to double the incoming frequency (which would be 16MHz in an LC/LCII/CC) to drive the new CPU (which is 33MHz here). Interware had a few cards that operated like this. Personally I don't know why they bothered with the one specifically for the IIvi (basically, at 33MHz with some cache, it turns it into a Performa 600) because it's such a tiny piece of an already tiny market but whatever. I have one though and I pondered using it in an SE/30 with one of the IIci adapters because it's faster than stock, especially with the SRAMs, but not as fast (or nearly as expensive) as the proper Booster 30-SE50F model, though the latter doesn't have cache which adversely impacts performance on that 16MHz bus.
 

Trash80toHP_Mini

NIGHT STALKER
I have one though and I pondered using it in an SE/30 with one of the IIci adapters because it's faster than stock, especially with the SRAMs, but not as fast (or nearly as expensive) as the proper Booster 30-SE50F model, though the latter doesn't have cache which adversely impacts performance on that 16MHz bus.
Very, very interesting that notion. If the GAL really is unlocked or we can look at it as a black box to decipher its logical functions we'd really have something. If I squint just right and some work (clueless about how much?) that looks a lot like a socketed accelerator with cache for my IIcx and spare SE/30. :p

@Bolle we can tell if it's unlocked just by reading it without worry about destroying it?
 
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max1zzz

Well-known member
Whatcha think turning that into a low budget socketed 030 accelerator might entail?
That was my exact plan :)

I'll start with a 1:1 clone, check it works than draw schematics from it and turn it into a low budget socketed card people can assemble themselves / that I can supply cheap without the CPU

The only shame is the MC88916 only seems to be available as a SOIC package, I would have liked a DIP one for ease of assembly

EDIT: That was a really long way of saying "really easy"
 

Bolle

Well-known member
There’s other ways to double a clock signal. If you’re going to redesign it anyways just use something else. A tiny RC network tuned to the source frequency to shift the phase of the clock by 90 degrees and then XOR-ing the original and the shifted signal will work (as long as you know the frequency - which we do in this case)
Or just use the propagation delay of a GAL or any other logic gate to generate a shifted signal.
 

Trash80toHP_Mini

NIGHT STALKER
That was my exact plan :)
I like the way you're approaching this, great ideas. ;)
Your Sprint(?) Layout Tracing->Prototype Testing->KiCAD Schematic Development->Board Rework process is the bombe!

Is there a larger (more lines) GAL available that could incorporate the Clock Doubling GAL's function on Performer, for an all in one package implementation?
 

Trash80toHP_Mini

NIGHT STALKER
Found it on the Radius NuBus Adapter IIsi:

GAL20V8A-25LP-Radius_NuBus.JPG

I knew there was a "20" version available, just couldn't think of it. Dunno if four more lines will allow folding the Performer's GAL16v8 PLL function into the 20 GAL? A lot of signals get looped back around on the pins.
 

max1zzz

Well-known member
Hmm I don't know is the answer, But I have exactly 0 experience with them so I'll leave it to one of the experts to answer :)

I do like the idea of just using a RC network + XOR though as it seems like a simple solution, though my question with that would be is the exact clock frequency important? AKA would high tolerance parts need to be used or could common cheapo carbon resistiors and ceramic caps be fine?
 

Trash80toHP_Mini

NIGHT STALKER
Just socket another of the same and switch SMT caps, resistors etc. for radials.
You'll have an all thruhole board kit that even I can solder together. 🤪
 
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