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

[rabbitholecomputing]

Following on from our full-sized ZuluSCSI RP2040, which we released back in November of last year (2022), we've got another entrant to the ZuluSCSI family, available for purchase today in kit form, starting at a mere $42, from https://store.rabbitholecomputing.com/ZuluSCSI-Compact-Homebrew-p/zuluscsi-compact-homebrew-kit.htm

ZuluSCSI Compact Homebrew is only available as a DIY kit, comprised of easy-to-solder through-hole components. Heat up your soldering iron and solder on the 50 pin internal SCSI (IDC) connector, capacitors, pin headers, and the berg/LP4 power connector, and you're ready to go. All surface-mount components are factory-assembled, and the SCSI interface on the board has been tested.

SCSI termination is controlled via DIP switch, as is Initiator mode.

Initiator mode allows ZuluSCSI Compact Homebrew to function as a SCSI controller, letting you attach almost any hard drive, CD-ROM drive, Zip/Jaz drive, magneto-optical drive, and make byte-for-byte copies of the contents of them. The firmware polls the SCSI bus for all available SCSI IDs, and, if found, writes them directly to an image file on the SD card.

ZuluSCSI Compact RP2040 is powered by the Raspberry Pi Foundation's RP2040 microcontroller, a dual-core 133MHz ARM Cortex-M0+ processor. Supports synchronous and asynchronous transfers, with read speeds up to 9 megabytes/second, and write speeds up to 6 megabytes per second. A SCSI controller with FAST SCSI and synchronous mode is required to achieve maximum speeds.

ZuluSCSI firmware is open-source, licensed under the GPLv3. See http://github.com/zuluscsi/zuluscsi-firmware or ZuluSCSI.com for more information.

ZuluSCSI Compact board dimensions are 90mm by 60cm. Nearly all mounting solutions that were designed for SCSI2SD V5.1/V5.2/V6, or the full-sized ZuluSCSI boards, will work just as well with ZuluSCSI Compact. The two front mounting holes on ZuluSCSI Compact are the same dimensions.

 

[macuserman]

This is awesome, extremely competitive price as well. Kinda hard to complain about anything on this one for the naysayers, very well done!

 

[3lectr1cPPC]

Agreed for sure, looks like a great product with unique features. Would definitely consider one, that is, if I actually owned any SCSI desktop macs, which I don't.... maybe that will change after the VCF swap meet in june though
Keep up the great work!

 

[Fizzbinn]

Initiator mode allows ZuluSCSI Compact Homebrew to function as a SCSI controller, letting you attach almost any hard drive, CD-ROM drive, Zip/Jaz drive, magneto-optical drive, and make byte-for-byte copies of the contents of them. The firmware polls the SCSI bus for all available SCSI IDs, and, if found, writes them directly to an image file on the SD card.

That. Is. Awesome!

 

[avadondragon]

Initiator mode allows ZuluSCSI Compact Homebrew to function as a SCSI controller, letting you attach almost any hard drive, CD-ROM drive, Zip/Jaz drive, magneto-optical drive, and make byte-for-byte copies of the contents of them. The firmware polls the SCSI bus for all available SCSI IDs, and, if found, writes them directly to an image file on the SD card.

Wow that is a cool feature! Any chance for being able to emulate a USB mass storage device too?

 

[joshc]

@rabbitholecomputing Will AmigaKit stock/sell these in the UK?

 

[rabbitholecomputing]

@joshc I certainly hope so, but if anyone else here would like to distribute kits in the UK, please contact via PM or e-mail.

 

[Ortho'sDeli]

I'm trying to get one to work inside of an external enclosure but I can't get it to be recognized by the system. I also have a full sized v1.1 that I'm currently using as an internal drive that I could switch out, but using the Compact as the internal seems to block any external devices from being recognized. Is there a way for me to modify term/ID to make it work?

 

[rabbitholecomputing]

@Ortho'sDeli Without knowing how you have it configured, it's impossible to help. How is it configured, currently? What model of ZuluSCSI is it? How isn't it being detected? Be as specific as possible.

 

[Ortho'sDeli]

Sorry, it's the new RP2040c that this thread is about. Configuration on it is a tested working preinstalled image on the SD. When inside the enclosure, attached via a DB25-DB25 cable, it'll flash SD not detected, yet if I directly attach it to the internal connection (same bus) it boots normally.

 

[aperezbios]

In that case, you should probably report it at https://github.com/ZuluSCSI/ZuluSCSI-firmware/issues

Please include a copy of the zululog from the device (when it detects the SD card) as it will contain answers to some of the most basic questions we'd otherwise have to ask.

Is it the only device externally? It would also be helpful to know the make and model of the SD card. Put all that in the issue

 

[aperezbios]

Sorry, it's the new RP2040c that this thread is about. Configuration on it is a tested working preinstalled image on the SD. When inside the enclosure, attached via a DB25-DB25 cable, it'll flash SD not detected, yet if I directly attach it to the internal connection (same bus) it boots normally.

Also, if the enclosure has its own SCSI termination, you may have a situation where you're double-terminating the bus without realizing it. If there's termination provided by the enclosure, you would want the termination on the ZuluSCSI itself to be OFF.

 

[Ortho'sDeli]

Also, if the enclosure has its own SCSI termination, you may have a situation where you're double-terminating the bus without realizing it. If there's termination provided by the enclosure, you would want the termination on the ZuluSCSI itself to be OFF.

Just submitted over on Git. How do I disable term for the compact since it has no dips?

 

[Ortho'sDeli]

User over there figured it out. Looks like it needed additional power.

 

[aperezbios]

User over there figured it out. Looks like it needed additional power.

He's actually the primary developer

 

[pizzigri]

Dear Zuluscsi developer,
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 poimt 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 berger) ps connector….
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 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. 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!

 

[robin-fo]

This is also my opinion..

 

[macuserman]

Dear Zuluscsi developer,
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 poimt 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 berger) ps connector….
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 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. 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!

Oooh!! Any chance you will sell these? Or make them available somewhere? I have the same problem. I’ve just been buying the full size ones because they are so much easier to mount.

 

[Daniël]

Third'd on that one. All SCSI emulator devices should have the PCB designed to be easily mounted in place of a hard drive, because, y'know, it'll be installed where the hard drive used to be. It's honestly kind of weird that multiple projects have not (always) kept it in mind, not just ZuluSCSI Compact. Some projects never did and it's super silly!

 

[pizzigri]

Oooh!! Any chance you will sell these? Or make them available somewhere? I have the same problem. I’ve just been buying the full size ones because they are so much easier to mount.

Well… I can post the gerbers, but it’s not something really sophisticated, I mean it’s two pcbs stacked that places the Zuluscsi all the way to the left (looking from the rear) and provide convenient holes for mounting on mac sleds...