ProtoCache1 - IIsi/SE/30 PowerCache Adapter Prototype Development

Trash80toHP_Mini said:

Just held it up against the open SE as if it were in the vertical passthru of my multi-slot AI models. It fits! [ ]

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FANTASTIC!  Woo-hoo!

I will chop off the +5V plane around the Cache connector and implement jumpers that let one connect it to the rest of the VCC plane.

If you chose to get your 5V for the accelerator from somewhere else you can plug in a floppy power plug which is connected to the 5V plane around the cache connector.

That way one can decide to run the accelerator from power supplied by the host PDS slot or an auxiliary power supply. The extra card on the passthrough as well as the MacCon sitting on the bottom will be powered from the host PDS slot.

If you leave out the additional card on top and only run MacCon+accelerator there is no need for extra power and you can set the jumpers to connect both VCC sections.

That's KISS right there if you ask me 

It’s beautiful! *wipes tear from eye*

Here's a scan of one of my Xceed cards with a measuring stick for reference.  Not metric, sorry:



Here's the low-profile HDD mounting "plate" I intend to use, with SCSI2SD mounted on top for that ultimate in anorexic getup:

Going to whip up something quick for power. 1 sec.

Nevermind saw bolles post

Sweet, thanks. NoPro on the inches. A 3" tank or anti-tank gun is 76.2mm, so your six inch ruler will be twice that for pretty easy scaling. Number associations can be very, very strange things. :

Bolle, have you looked at the mounting ear complications for your layout? I'll get your layout into Illustrator. In the meantime, print it out, paste it up to cardboard and lay that with your wrong angled NIC on top of your GS Card to determine the points of interference.

Looks like you need to convert the mounting holes for your bottom slot connector to the RA connector configuration mirroring your female passthru connector provisions on top?

I wouldn't use headers for power connections, pretty sure they're not reliable enough anyway. I'd add thruholes for soldering nice fat copper jumper wires if anyone wants to overtax PDS Power spec by running more than two cards. Normally I'd say put butterfly traces on outer layer in your layout to be easily cut when adding aux power. But in this case I'd leave both options "open" for a user to make a conscious decision as to which route to take at their own risk. KISS is good CYA is better. [] ]'>

Hey K55, if you have an idea, throw it out here.  We're in the primordial soup phase!

joethezombie said:

*snip*

and the pull-up/down resistors:

*snip*

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Those are:

R1 1,2kohm   pull up /BGACK

R2 390ohm    pull up /RESET

R3 680ohm    pull up /BERR

R4 680ohm    pull up /HALT

R5 1,2kohm   pull down CPUDIS

Correct?

Numbers in your picture are a bit hard on the eye.

Values verified, Bolle!

You guys kick ass. Awesome job joe, jt and everyone else working on this! 

THX, mj, your support and that of others all along has been a great help.

IRQ 1/SLOT $9 = available on SE/30 PDS
IRQ 2/SLOT $A = available on SE/30 PDS
IRQ 3/SLOT $B = available on SE/30 PDS

Holy crap! Just went back to confirm that three slot interrupt/Slot ID availability on the PDS and realized this will very soon have been a three year roller coaster ride! 8-o

Added the capacitors and worked out the CACHE signal.  Note the added pull-down and detached state of the CACHE signal across the THRU slots.

The original card has additional capacitors located at the FPU socket, which I have omitted.



EDIT:

Next steps-

1.  Triple-blind-check and make sure everything is in order.  For this, I will remove all the components from the board so I get no interaction from resistors or capacitors while I noodle it all out.

2.  Try the adapter with a dual PDS riser and see if I can truly run two PDS cards and a PowerCache without issue.

3.  Design the cards.  Bolle has done a damn fine job on the PowerPerch™ adapter.  I have a few ideas for my TripleNipple™, and I know jt has some great things coming as well.

You'll probably want to decouple all of the power lines at least once and put a big decoupling cap near each 5v line near the 3 sockets. Thats around 7 or so caps, which you can clearly see on the twinspark .

Great input! I'm still fumbling about with the two TTL input driving restriction specification for the PDS. Overloading the spec by 50% for adding another passthru is one thing, but expecting the PDS to handle inputs for three passthru slots seems more than a bit excessive.

Been looking for a TTL driver chip but was wondering:

-- am I looking at this from the wrong direction?

-- should I be looking at the input driving capacty of the PowerCache?

-- It's the accelerator that will be driving the inputs of the expansion cards, no?

-- have we got any spec on the input driving limitations of the PowerCache?

-- might this be problematic?

I'm now wondering if TTL drivers might be needed for the PowerCache's output lines as opposed to those of the PDS?

DCaDftMF states signal buffering should occur on the expansion card, so i’m operating on the assumption that the cards were designed that way.

But I am curious, what three PDS cards would you attempt to install? Video and Ethernet are a given, but what else even exists?

Another ethernet card for routing capabilities or another video card for multi-monitor setups

Those IIsi pivot cards are pretty small, there would fit a lot of those in there.

I was going to add some more caps than the ones that are needed near the slots anyways. I also have been looking at line drivers that might be suitable. What lines should be send through those? Adress and data bus only or all other signals as well? We will need a lot of buffers if we want to run all signals through one.

Edit: Regarding the whole two cards + accelerator issue. Gamba did run grayscale, ethernet and powercache back in the day I think. It just did not fit inside the case with the adapters and wrong-angle wizzardry they had to go through.

joethezombie said:

But I am curious, what three PDS cards would you attempt to install? Video and Ethernet are a given, but what else even exists?

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h34r:

NuBus?  Oh boy...

NuBus! Heh!  [] ]'>  A man's gotta have an impossible dream! This windmill has been rocked to its foundations and that rubble is soon to be blown away after a three year campaign. Time for bashing my head on another one that's been in the works for a while  .  .  .  about five years on and off. :