ZuluSCSI Compact Homebrew - A Smaller, Faster, and More Capable RP2040-based SCSI emulator

[rabbitholecomputing]

I purchased two of these boards, however I do have a little gripe about the layout, please don’t flame me….
so look at the images, I noted that this seems to be a trend about most makers, the circuit is fantastic, the design also etc etc…. But, everyone assumed these will live by themselves, as if the whole point is to make them central to the machine the user will employ them in. however, and the Zuluscsi is better than most, these things replace hard drives, in places where hard drives normally are housed, and powered with either term power or the molex (not berg) ps connector….

Thanks for the contribution, and the feedback. The community would definitely benefit from you sharing the Gerbers. It should be noted that both the full-size ZuluSCSI (and SCSI2SD V5.1/V5.2, SCSI2SD V6) all are designed to with the standard bottom-facing 2.5" mounting holes, as specified in the SFF-8201 specification, on pages 8 and 9. This allows you to use many, many off-the-shelf 2.5" to 3.5" mounting brackets.

In almost every case, with almost every Mac, no external power is necessary, by design, as nearly every mac supplies SCSI termination power both internally and externally, as do most other non-Macintosh SCSI controllers.

There's a reason why we sell ZuluSCSI without the Berg connector by default; It isn't needed in most scenarios, and it adds needlessly to the cost of the board. This is precisely why it's optional.

so why not make a pcb that replicates the hd layout? In this case, I built an adapter (actually jlcpcb made it for 2$) to mount the zuluscsi to a standard Mac sled - the Berger

I think you mean Berg (floppy-style), since there's no such thing as a connector.

connector is thankfully on the correct side (vs someone else’s scsi to sd adapter) , but the connector should be at the very edge of the pcb and not inside by 8mm - so that tight fitting cables should unnaturally bend to reach the connector, as is the case for the Color Classic.

When assembled, the IDC50 connector _is_ at the very edge of the board. I assume you're referring to the location of the footprint itself, relative to the edge of the board. Such a change would make it significantly more difficult to correctly assemble the IDC50 connector and have it be at a perfect right angle. Such a change would increase the difficulty for most people assembling the board. Your mounting solution solves your concern.

I apologize for the rant, but when something is made so well even a little cut corner becomes a sore thumb. Thank you for the Zuluscsi, I just love it!

I don't see it as a rant, but I do see it as somewhat of an "only my specific use cases matter" critique. When designing a product, there are many other factors to consider, when designing a product. Manufacturability and cost considerations are equally, if not more, important.

 

[pizzigri]

So here are the gerbers. The PCB is in two parts, one is broken off and stacked on the other to provide better clearance and mounting ease. There are no markings on the part that can be broken off otherwise JLCPCB will charge double (as two PCBs... argh), but this way five boards cost 2$ - plus shipping of course.
Now, to my "rant". Weird syntax in my post - the friggin' keyboard is TINY and i'm 55 years old without glasses. I'm actually amazed I managed to avoid embarrassing myself more than that. I use a phone as it's easier to add pics directly from the camera without an extra passage on the PC. However, I may have expressed myself poorly as well, especially in regards to which "edge" I was referring to. You have conveniently placed your copyright information on the corner of the board, the left hand corner looking the ZuluSCSI from the IDC50 connector facing you.
The point is, there's nothing there - except your support info. So, my gripe and it's NOT a critique in my single use scenario, is that the IDC50 connector would align much better to cable placements in most Macs simply by moving said IDC50 left until the corners of the PCB and the connector align.
And in the truth that is a picture is worth a thousand words....

 

[macuserman]

Thanks for the contribution, and the feedback. The community would definitely benefit from you sharing the Gerbers. It should be noted that both the full-size ZuluSCSI (and SCSI2SD V5.1/V5.2, SCSI2SD V6) all are designed to with the standard bottom-facing 2.5" mounting holes, as specified in the SFF-8201 specification, on pages 8 and 9. This allows you to use many, many off-the-shelf 2.5" to 3.5" mounting brackets.

In almost every case, with almost every Mac, no external power is necessary, by design, as nearly every mac supplies SCSI termination power both internally and externally, as do most other non-Macintosh SCSI controllers.

There's a reason why we sell ZuluSCSI without the Berg connector by default; It isn't needed in most scenarios, and it adds needlessly to the cost of the board. This is precisely why it's optional.

I did not realize this, I just checked with some adapters I have and this is going to make mounting these a cinch. That would be some really good info to put on your product pages on the store. Shoot see if Pizzgiri cares if you offer that adapter board as a checkout option on your drop-down, I'd gladly pay an extra few bucks to avoid having to order an adapter separately later. Either way, it's super nice to know I can use an off-the-shelf 2.5 to 3.5" adapter. BTW not knocking your stuff I love the zulu, trust me I have a pile of them!

I do wish that your store page more info on differences between your different offerings though. A comparison feature list would be awesome, there are several little gotchas which you don't notice without really looking, like compact, vs homebrew are not the same layout but with the through hole components left for you to do yourself, which is what I thought for a long time. They are actually totally different and the compact doesn't have a physical jumper for TERM.

Just stuff like that, or that your designs use standard holes and regular adapters will work etc would be cool to have spelled out. Either way I'll probably keep buying! lol

Just a few that aren’t buried in machines!

 

[olePigeon]

I would love to have a variants that're an easy PCB swap for old Quantum drives. Take a broken drive, then just swap out the PCB for the SCSI emulator.

 

[macuserman]

I would love to have a variants that're an easy PCB swap for old Quantum drives. Take a broken drive, then just swap out the PCB for the SCSI emulator.

That seems like a nightmare as far as how many drive variants are out there etc. Also I think it's important to keep in mind that while this is a mac forum, these get used in all sorts of other machines as well that aren't quite as similar. He has to manufacture somewhat standard stuff that can be used generically, I personally am thrilled to know that I can use a standard 2.5 to 3.5" adapter I feel like a dope for not realizing it sooner. Checkout Sampler Zone if you want to see some really funky cases for other use cases just as an example. https://samplerzone.com/collections/zuluscsi

 

[olePigeon]

I get it, it was just a wish list. Like if I had a few extra dollars to do a one-off, it would be neat. Coupled with the HDD clicker, it'd be neat.

 

[rabbitholecomputing]

I did not realize this, I just checked with some adapters I have and this is going to make mounting these a cinch. That would be some really good info to put on your product pages on the store.

Agreed. The product description for the full-sized ZuluSCSI RP2040 now includes the following:

The four M3-sized mounting hole dimensions are identical to those found on the bottom of any 2.5" hard drive, meaning you can use most commodity 2.5" to 3.5" mounting brackets/adapters to mount ZuluSCSI.

Shoot see if Pizzgiri cares if you offer that adapter board as a checkout option on your drop-down, I'd gladly pay an extra few bucks to avoid having to order an adapter separately later. Either way, it's super nice to know I can use an off-the-shelf 2.5 to 3.5" adapter. BTW not knocking your stuff I love the zulu, trust me I have a pile of them!

We'd be happy to, but without an explicitly-defined license, we can't and won't use anyone else's designs in a commercial context.

I do wish that your store page more info on differences between your different offerings though. A comparison feature list would be awesome, there are several little gotchas which you don't notice without really looking, like compact, vs homebrew are not the same layout but with the through hole components left for you to do yourself, which is what I thought for a long time. They are actually totally different and the compact doesn't have a physical jumper for TERM.

There is a comparison table currently, but not on the product pages, at present.

Something like this table, as seen at https://github.com/ZuluSCSI/ZuluSCSI-firmware/wiki/ZuluSCSI-Manual#introduction-features ?

Hardware Version/Edition	RP2040	V1.0	V1.1	V1.1 Laptop & RP2040 Laptop	V1.0 Mini & RP2040 Mini (DB25)	RP2040 Compact	RP2040 Compact Homebrew
DIP-switch/jumper-configurable SCSI termination	Yes	Yes	Yes	Yes	Always On	Yes	Yes
LED pin header location for optional external LED pin header	Yes	Yes	Yes	Yes	No	Yes	Yes
SD Card Type	Full Size	Full Size	Full Size	MicroSD	MicroSD	MicroSD	MicroSD
Initiator Mode	Yes	Not supported	Not supported	Not supported	Not supported	Not supported	Yes

It would not be difficult to put a version of that table in a more-visible place. The original ZuluSCSI Compact was designed and manufactured prior to the introduction of BSv2, and the Homebrew version of ZuluSCSI Compact is a less-cost-reduced version, which restores the ability to have jumper-enabled/disabled SCSI termination, as well as SCSI Initiator mode support.

Just stuff like that, or that your designs use standard holes and regular adapters will work etc would be cool to have spelled out. Either way I'll probably keep buying! lol

Totally understandable. The mounting hole dimensions for the full-sized ZuluSCSI boards are directly descended from the SCSI2SD V5.1 board design, FWIW...

 

[pizzigri]

I have absolutely no problem in someone using that design commercially. Only thing I ask is that the adapter carries the Pizzigri text. If I need to sign off a license, there’s no problem - also for modifications on the basic design.

 

[pizzigri]

...and since the RabbitHoleComputing guy mentioned a form factor standard, i took a look at SFF-8301 Rev 1.9 just to be on the safe side and got again some dimensions from the ZuluSCSI Compact to be sure I did not mess up. So I also added clearance for the buzzer, Term_en, Buzz_en soldered pins and changed slightly the board size (if you keep the size under 100x100 or very near this the price is about 2 US$).
So here is the updated Gerber, please use this.

ETA: Ooops no gerber file. Here it is

 

[tt]

- delete

 

[pizzigri]

Hello tt,
since you're post is... enigmatic, to say the least, are you requesting I delete the above files?

 

[Phipli]

Hello tt,
since you're post is... enigmatic, to say the least, are you requesting I delete the above files?

It's because you can't change your mind when you make a post. They've edited it to mean they changed their mind and aren't posting... But can't get rid of the post.

"Deleted post" might have been more clear. But it isn't to do with your post, don't worry

 

[tt]

Sorry, I made two arbitrary taps on my trackpad and accidentally made a post and couldn't find a delete button, so I am hoping a mod could delete it for me. The forum can lose posts with useful user contributions without a proper backup but we can't get a delete button

But now I have a question, does @rabbitholecomputing plan on using the wifi version of the Pico micro in this product or others? The SCSI-Ethernet emulation looks interesting and would be nice for Macs like the Classic, Plus, etc. Maybe the external DB25 version makes more sense for the RF signal.

 

[MindWalker]

I have two of the Homebrews (and soon a thrid) and I like it

In case somebody finds this useful; I created a small 3D-printable frame to give the Homebrew PCB some protection. I've been using mine at the end of a long SCSI-cable as an external device and it's been flapping around in the breeze and I wanted to give it some protection against accidentally shorting it. Of course the frame can be mounted down with double-sided tape or velcro etc as well.

https://www.thingiverse.com/thing:6562403