SillyTinySCSI Centronics 50

Started by hiker, February 02, 2024, 10:29:40 AM

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hiker

Since I got my CZ600CE I have been using a BlueSCSI V2 Centronics 50 Pin.
A couple weeks ago I came across https://github.com/ZigZagJoe/SillyTinySCSI, a small variant of the ZuluSCSI Pico, over at 68kmla.org. So I decided to make a Centronics 50 variant of it.
Below are the results, haven't spent much time testing. It can be powered by the Pico's USB port or from term power (but that requires a modification of the X68000).

Not sure about the location of the SD card slot.
My further plans are to test it a bit more, and see if it physically fits a FM Towns tower (which I don't have yet).
Also thinking of adding another layer that adds CD audio output via https://github.com/saybur/dac-attack (I'm using this in my IBM PC).

I pushed the current version to https://github.com/hkr/SillyTinySCSI-Centronics50.
 

16bitgium


rabbitholecomputing

Very nice, came here to say great work. It's so great to see our OSHW hardware design evolve like this.

opooly

Hi Hiker,

I got a CZ600CE as well since few months now and I was not sure which solution to use (SCSI2SD, BlueSCSI, etc).
This SillyTinySCSI looks good, is it working out of the box? Is it working fine with the SxSI-SCSI HDD Image v2.10 ?

Thanks
Jon

hiker

Quote from: opooly on February 10, 2024, 03:48:25 PMI got a CZ600CE as well since few months now and I was not sure which solution to use (SCSI2SD, BlueSCSI, etc).
This SillyTinySCSI looks good, is it working out of the box? Is it working fine with the SxSI-SCSI HDD Image v2.10

Since only one prototype of this exists so far it's safe to say that if you want something that is guaranteed to work then look elsewhere :).
That being said, I'm using the "SxSI-SCSI HDD Image v2.10" image and it works, not noticed any difference compared to the BlueSCSI Centronics 50 I used before. I also never had any issues with the BlueSCSI and I had picked it because it was the only one I found with a Centronics 50 connector.

My only gripe with the BlueSCSI Centronics 50 is that the micro SD card slot is below the Pico.
But it is easy to insert the SD card not into the card slot but in the gap between Pico and slot cover. And then it's hard to get it out again.
Granted, I got the version that didn't come pre-assembled, so maybe I made a mistake there and should have left a larger gap.

kamiboy

This is pretty cool and nice fit for the Tower models. I am really not much for having a huge ugly contraption awkwardly sticking out from my machines, but this low profile jobby I wouldn't mind, especially if paired with a sleek 3D printed case.

The only hitch is this mod that is required to power it fully from the X68000. What is this mod? I assume it is some pin on the SCSI connector that needs to be connected to a 5V line on the motherboard?

aotta


hiker

I'm using the mod that @aotta linked. But I think with a short cable and small USB power brick in the pass-through power socket, ideally angled in the right direction, it would also be ok.

I don't have a 3D printer and also lack the skills to design a case, so my plan was to just add a cover PCB, leaving sides exposed. If anyone wants to help designing a case, please let me know :).

For a while I was thinking about trying to cram everything into a SCSI terminator which usually come with a case. But that would probably require a completely different board design.

I looked a bit into supporting CD audio but the stock Pico doesn't expose enough GPIOs.
Olimex makes a variant that replaces some of the ground pins with more GPIOs. In any case it would require a custom build of the ZuluSCSI firmware. I will probably try this at some point.

kamiboy

You lost me on the CD audio thing. What does that mean exactly? How would it work on the X68000, and what would it do?

hiker

CD audio is not relevant for the X68000.