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RaSCSI Development Thread


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Figured I'd get this one started. I've just finished up the board design for an implementation for the RaSCSI device as seen here http://www.geocities.jp/kugimoto0715/rascsi/index.html

 

Schematic:

post-4241-0-42376800-1493846588_thumb.png

Board:

post-4241-0-48160400-1493846541_thumb.png

 

Sorry about the messed up wires on the top, had to re arrange stuff to make the board layout easier.

This design is going to use the 4 74ls641s. They run about $3 each and with everything else + pcb; $20 would be the at cost price.

 

If anyone's interested I'll be ordering 10 (ish) copes tomorrow. I'd probably sell for around $30ish.

 

The one benefit for this over the scsi2sd is that I think a raspi is more accessible and available to people than the other SCSI emulators on the market,

and that this can be updated with new GPIO updates etc, and improved in software. |)

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This design is going to use the 4 74ls641s. 

Glad to see you using SMT instead of DIP

 

Two suggestions:

- Add a second set of board mounting holes that aligns to the Pi, to allow for spacers to keep the SCSI pins from getting anywhere near the conductive surfaces of the HDMI port and similar.

 

- Use a right-angle SCSI connector such that this actually might be able to be mounted somewhere where a HDD might fit that has cable clearance out the back, but none to the top.

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V1.1 Update: now has 4 headers and a molex connector for power from the mac itself.

post-4241-0-11292900-1493864409_thumb.png

 

Edit: This would work as long as you had enough clearance for the SCSI plug. I'm going to work on a right angle version but it'll probably push up the cost a dollar :cc:

Edited by K55
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A little confused about the placement of the second set of mounting holes as they don't seem to line up with the PI mounting holes, or am I mistaken?

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They're holes for the zero model, that's the aim anyway. I can fit in the regular holes, but its 2am and Im tired

V1.2 with a right angle connector, had to rework the entire board, also switched to the mini 4pin floppy (thanks jt)

post-4241-0-92249900-1493879060_thumb.png

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LOL! I've already bounced another LED hack off K for that nifty little bit of prototyping real estate! Thanks for the suggestion, SMT LEDs right on board with a one piece printed coverplate might work out great for it.

Edited by Trash80toHP_Mini
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LOL! I've already bounced another LED hack off K for that nifty little bit of prototyping real estate! Thanks for the suggestion, SMT LEDs right on board with a one piece printed coverplate might work out great for it.

 

:D  Well, I designed the Jolly Roger that's used on a couple homebrew projects.  Since I'm a liberal arts major, it was the only thing I could contribute to these awesome projects.  So far, DougG3's original SIMM is my favorite implementation with the glowing red LED eyes.  It's just too cool.  I'd love to get a proto-clear lid for my IIci so I could see it all the time. :p

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I love the red glow of mine too, but when I'm around them my boxes the hoods are almost always popped. Love your design. Workin' on a Clear IIfx lid, got access to a CAD/CAM milling rig?

 

Liberal arts major here too/fine arts minor, it's not a bug it's a feature! Also frees the mind from conventional fetters, especially at a Jesuit school! ;D

Edited by Trash80toHP_Mini
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Does this have to be connected to a Rasberry PI?  Or can it work like a SCSi2SD?  Can I update it without a Pi?

 

 

Its made to work with any pi B+ fowards, so the 2,3, zero etc. Makes things flexible.

We'll see about software once I get the HW in and can work with the original dev's drivers.

 

JT would breakout points for the activity led be ok with you?

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I personally wouldn't even have bothered supporting the zero, considering how slow it should be, given the 1MiB/sec was measured off a Pi3, and GPIO speeds are bound to the cpu speed, but who knows....

 

I'm working on a different style project using RaSCSI so don't worry, I won't be overlapping once I get my pcb finished- put me down for one of your boards as well though.

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Sure, just put in thru-holes for header pin installations for:

 

Power 5V & 3.3V are available on the board, correct?

HDD Activity

Fill up the added real estate on the side with a prototyping area just for kicks.

 

Breaking power and HDD activity out to a header will give oP the chance to print up some 3D skull-n-pistol sticky badge dongles for his LEDs. Put the Logo Dongle on wire wrap wire and thread the leads out through the power LED light tube opening and he'll be a happy camper.

 

Somebody can figure out how to drive 'em at 3.3V/whatever whenever the computer is on then and kick 'em up to the full 5V whenever there's a disk access blip fed to an adapter circuit in the proto area. Maybe just a couple of gates? He'll be friggin' thrilled. [:D]]'>

 

Do I see any mechanism for SCSI Drive ID settings?

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Sure, just put in thru-holes for header pin installations for:

 

Power 5V & 3.3V are available on the board, correct?

HDD Activity

Fill up the added real estate on the side with a prototyping area just for kicks.

 

Breaking power and HDD activity out to a header will give oP the chance to print up some 3D skull-n-pistol sticky badge dongles for his LEDs. Put the Logo Dongle on wire wrap wire and thread the leads out through the power LED light tube opening and he'll be a happy camper.

 

Somebody can figure out how to drive 'em at 3.3V/whatever whenever the computer is on then and kick 'em up to the full 5V whenever there's a disk access blip fed to an adapter circuit in the proto area. Maybe just a couple of gates? He'll be friggin' thrilled. [ :D]

 

Do I see any mechanism for SCSI Drive ID settings?

 

ID is set in software, still looking at the software side, will probably understand it at some point, SCSI isn't that complicated :p

 

V1.4: Added in breakout header for JT, tided up some minor errors, and added in snazzy artwork. It's probably done at this point, so I'll order it tomorrowish and expect it to be here the 1st week of june approx.

post-4241-0-21284200-1493960608_thumb.png

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with the wider board, Is it going to run into the ethernet/usb jacks?

It goes under the raspi, but it should be fine ;)

 

V1.5: I got the correct floppy power connector from the SCSI2SD guy so its thinner now (aka around the width of a raspi B+-2-3) :D

post-4241-0-27056600-1494029743_thumb.png

 

Just ordered this version, so I should have 10 or so copies by next month.

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CAD, but the old version. I'm trying to learn OrCAD and Altium Designer also. Its really you use what you find most conformable.

They all arent super user friendly, but altium designer has the best toolkit for really testing a design (with rules and the like).

 

I order almost all my pcbs from dirtypcbs, or electrow usually. This time I used electrow.

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Do you use free versions that are good up to certain board size limits for open source projects like this? What are max sizes for PCB layouts and board fabrication within that licensing scheme? Most projects seem pretty tiny to me. I'm used to seeing a lot of DIP 74LS and discrete thru-hole components on boards no smaller than a short 8-bit ISA card. 100mm x 100mm seems tiny. :-/

Edited by Trash80toHP_Mini
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