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Anyone know if you can install a Brainstorm in a 512k? Is it compatible with a Hyperdrive?
Posted by: olePigeon on 2017-09-13 09:56:24
Interesting conundrum that I don't know if anyone has an answer to.

First, can you install a Brainstorm accelerator into a 512k?

Also, anyone know if the Hyperdrive is compatible with a Brainstorm accelerated Plus (or 512k if that's possible.) ?
Posted by: 360alaska on 2017-09-13 18:46:04
Doubtful, the Brainstorm accelerator actually has its own eeprom built in, For that reason its unlikely that any add on which utilizes rom hacks will work.
Posted by: Trash80toHP_Mini on 2017-09-14 14:12:31
I can't think of a reason a Killy Klip upgrade won't fit in a 512k, but It would likely need the ke upgrade to noodge it a bit closer to Plus spec. Although what you might be interested in doing with a 16MHz upgrade within 512k of RAM escapes me.

Off the top of my head, the Hyperdrive would seem incompatible physically?
Posted by: Gorgonops on 2017-09-14 15:30:11
Doubtful, the Brainstorm accelerator actually has its own eeprom built in, For that reason its unlikely that any add on which utilizes rom hacks will work.
I just googled up a picture of a Plus Brainstorm and it looks like it just has one chip other than the CPU (described as an ASIC in reviews, but I kind of wonder if it's actually just a PAL with the numbers filed off). Does it have another chip hidden on it somewhere/does the ASIC have some NVRAM registers in it? It definitely doesn't look like there's enough to it for it to be performing any on-the-fly ROM patching. (My *guess* is that ASIC is just a soft-switch for fast/slow that's triggered by the software driver, and it also may have some hardcoded address line snooping to switch into slow mode when the CPU is accessing hardware devices? So far as I'm aware the peripheral memory map in the 512k and Plus match other than the addition of the SCSI controller.)

Assuming the Brainstorm really doesn't have any explicit dependency on the ROM or something about the Plus memory map that's different from the 512k I can't really see, in principle at least, why you *couldn't* in theory stack it with a Hyperdrive interface card, but as Trash points out there are major mechanical issues, and possibly electrical ones. The Hyperdrive board attaches to the original 68000 with a clip, while the example of a Brainstorm installation I see shows it plugging into what looks like a machine pin socket soldered to the original CPU. Obviously putting the Brainstorm on top of the Hyperdrive clip isn't going to work, and... I honestly don't know what the implications are of trying to clip the Hyperdrive to the CPU on top of the Brainstorm, assuming it's mechanically possible. If the Hyperdrive in any way depends on the clock signal supplied to the CPU then I see rough seas ahead. If it doesn't care about that then... maybe?

Also, it appears the Brainstorm relies on a jumper wire that connects somewhere to the timing circuitry on the motherboard. To install it in a 512k you'd have to noodle out where the equivalent place to anchor that is. Again, though, the systems are enough alike I can't give a good reason why it wouldn't work.
Posted by: olePigeon on 2017-09-15 10:57:59
I was just curious.  You'd absolutely have the fastest 512k out there if it worked. 😉

Posted by: Gorgonops on 2017-09-15 11:35:13
This is probably a silly question, but in the pictures of a Hyperdrive setup I can find there's wide ribbon cable connecting the controller board to the clip that goes on top of the CPU. It looks like in some of those pictures that you should be able to unplug that cable from the board. If that's indeed the case then I'd probably suggest the following approach:

1: Get the Brainstorm working in a 512k. Physically that's going to involve soldering the machine pin socket to the original CPU, as in the Plus installation I saw and, as noted, figuring out the appropriate place to anchor that flying resistor. (Anyone have the installation manual for a Brainstorm sitting around somewhere?) An interesting question is of course whether the control panel for it would work in an OS version supported by a non-e 512k, or if you'll need a 512ke.

2: Once you know the Brainstorm works you'll proceed to design a replacement for the CPU clip that consists of a PCB board that has through-holes for a 64 pin socket and routes all the pins to a header you can plug your ribbon cable into. Leave enough clearance for the Brainstorm between the socket and the cable header. Order it from your favorite PCB supplier.

3: When you get it, solder ribbon cable header pins and a *wire wrap* DIP socket, IE, the one with the really long legs, like this:



to the board. Plug the Brainstorm into the socket, plug the whole sandwich into the machine-pin socket you soldered to the original CPU, re-attach the Brainstorm's flying resistor, and cable up the Hyperdrive. And that's how you do a turkey.
Posted by: Gorgonops on 2017-09-15 11:36:45
... of course, while you're at it you might as well piggyback another set of RAM chips onto the existing ones and turn your 512k into a 1MB. (At least! I've seen instructions for stacking it up to two MB, why not really go for the gold?)
Posted by: trag on 2017-09-15 11:57:40
On the underside of the Brainstorm board, between the rows of connector pins, there are two very flat TSOP Flash chips, IIRC.
Posted by: Gorgonops on 2017-09-15 13:25:21
On the underside of the Brainstorm board, between the rows of connector pins, there are two very flat TSOP Flash chips, IIRC.
If true I suppose that would probably answer definitively whether it would work with a 64k ROM or not. Doesn't *necessarily* settle the question whether it would interfere with a Hyperdrive or not. They did make a ROM upgrade for the Hyperdrive to work with the 128k ROMs, and I believe (based on nothing but some very vague and possibly imagined memories) the Hyperdrive uses a mechanism in the ROM for dynamically finding ROM extensions, not by patching it per-se.

I do sort of wonder in the Brainstorm's case if how it works is the installer copies the whole ROM into its local cache (after applying patches) and overrides access to the physical ROM sockets. Depending on how that's implemented maybe that could lock it out from finding the Hyperdrive's ROM extensions? Without documentation it's impossible to know.
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