RaSCSI Development Thread

[K55]

Yep the X is the dot/ground pin. Just a standard SIP resistor array.

eg:

https://www.mouser.com/ProductDetail/Bourns/4610X-101-221LF?qs=sGAEpiMZZMvrmc6UYKmaNVaHnB8Kz7%2bapsej3SXibYs%3d

https://www.mouser.com/ProductDetail/Bourns/4610X-101-331LF?qs=sGAEpiMZZMvrmc6UYKmaNUXZLNzTfjvk1PNWiKwz6FM%3d

 

[olePigeon]

I like the use of the SIPs.  Old school SCSI.

 

[MrGasS27]

Here:View attachment 23170

I need to do them for SCSI2SD (SIP-10 bussed resistors cost a lot here in Italy) but I need 100 ohm for recreating the 4610X-101-101LF, I need only to put 100 omh resistors in each pin? (except the first, obviously)

 

[CRP]

Hi, I finally got together all components and am almost ready for assembly. Just for the heck I decided to check the the raspberry pin connectors and I'm not sure I understand them. While D0-D7, DP, CD and ACT are where I expect them to be the rest of the pins are not. Looking at the original japanese schematic, pin 13, corresponding to GPIO 27, should be for SEL, but on your board it is connected to ATN; equally for MSG (@ GPIO22, but should be REQ), SEL (@GPIO19, which should be ATN), IO (@GPIO26, BSY), RST (@GPIO21, should be ACK), ACK (@GPIO20, should be RST), BSY (@GPIO25, should be IO), REQ (@GPIO23, should be MSG).

I'm a newbie at this stuff so maybe I am mixing things up, can you please help me understand if these connections are correct?

 

[K55]

Yeah you're right, they're swapped. From the looks of it I reordered the output pins at some point and that changed the order of the input pins also.... (e.g. the wire change updated the whole net vs just the one wire). :O :O

 

[CRP]

I also checked the DB25 SCSI pins and they are correct. So the only consequence is that I can not use a standard 40 pin ribbon cable to connect the rascsi to the raspi, but have to set the pins one by one with a bunch of duponts, right?

Or I could cut the "wrong" traces and connect with some wire to get back the standard raspi layout?

 

[Trash80toHP_Mini]

Cut and patch the two traces, that's olde school. t would be easy enough to open up one of the IDC connectors and swap the two lines on the ribbon cable. But you'd run the risk of using the wrong (unmodified) cable somewhere down the line, so hot glue the modified end of cable to the lineswapped PCB if you go that route.

You've passed the protoboard litmus test with flying colors. One layout patch minimum required to qualify as a development board. :approve:

 

[K55]

For anyone wondering I haven't really had the time to work on the board. Work is eating up a lot of my free time but I'll make an effort this week to try and get it done.

 

[synchromesh]

This is great, thanks for doing this K55! I'm definitely interested in building a couple of these (one for a Yamaha AW4416, one for an E-mu ESI-32).

 

[Trash80toHP_Mini]

Subject of high prices for the real deal came up in another thread, dunno if it's been covered yet? Could the pi be used as a SCSI<->USB converter, non-trivial development?

Was curious, bump time anyway, LOVE it. :approve:

 

[bertie]

Has anyone tried the Direct Connection method described on Gimons site? ( http://www.geocities.jp/kugimoto0715/rascsi/index.html ) 

 

[Torbar]

Has anyone successfully gotten this to work on a Mac yet?

I have a question with how this works if I have some boards made.  Is the pi getting power from the floppy connector through the GPIO pins?, or does it need its own power source.  I'm assuming the former since it appears the power line of the floppy connector goes to the 5v GPIO pins

If so, can this replace the main internal HD on a Mac and have it boot off of that?  If so, I'm assuming the pi needs at least a few seconds to boot into the OS.  How does the Mac handle that.  You turn on the Mac, which powers up the Pi.  Does the Mac know to keep looking for the hard drive as the pi is booting up, and once that boots up it will auto boot from the disk image?

 

[Michael_b]

Also very curious about this. 

I don't have much experience in PCB design/fabrication, and my Japanese isn't very good... But in addition to SCSI emulation, the Raspberry Pi could provide internet access over serial.

Also see this thread regarding internet.

The PL2303 USB - Serial boards are a mere $0.58 shipped (!) on Aliexpress. The USB port on these could be removed and one could solder the board directly onto a RaSCSI PCB, to be connected to the Raspberry PI USB port. A mini DIN8 connector on the PCB could allow direct connection to 68k Macs. Though slow, an All-In-One networking + storage provider could be very useful for these old Macs

 

[Torbar]

Has anyone successfully gotten this to work on a Mac yet?

I have a question with how this works if I have some boards made.  Is the pi getting power from the floppy connector through the GPIO pins?, or does it need its own power source.  I'm assuming the former since it appears the power line of the floppy connector goes to the 5v GPIO pins

If so, can this replace the main internal HD on a Mac and have it boot off of that?  If so, I'm assuming the pi needs at least a few seconds to boot into the OS.  How does the Mac handle that.  You turn on the Mac, which powers up the Pi.  Does the Mac know to keep looking for the hard drive as the pi is booting up, and once that boots up it will auto boot from the disk image?

bump. 

Internet would be nice, but to me at least that's not as important as HDD emulation

 

[rabbitholecomputing]

bump. 

Internet would be nice, but to me at least that's not as important as HDD emulation

Or you could just go with a SCSI2SD V5.1, which is instant-on, and mature firmware that's 5+ years old. And the firmware is open source.

 

[Torbar]

Or you could just go with a SCSI2SD V5.1, which is instant-on, and mature firmware that's 5+ years old. And the firmware is open source.

I've definitely considered the SCSI2SD and will probably go with that for some of my machines, but I have a good amount of machines that I don't use often enough to justify the $50+ pricetag on.  

 

[Forrest]

Inertialcomputing has a good point. A Raspberry Pi 3 B+ costs $35. Figure $25 to order the RaSCSI board and parts and you're already matched the cost of the SCSI2SD V5.1, which is $59.99. Then you'll need to develop the software to use RaSCSI.

 

[rabbitholecomputing]

In addition, you can easily use one SCSI2SD across multiple macs, and this is especially easy if you buy it with the DB25 connector installed, and use it externally.

 

[Torbar]

Good point on using it externally, never even considered that to be fair.  

Inertialcomputing has a good point. A Raspberry Pi 3 B+ costs $35. Figure $25 to order the RaSCSI board and parts and you're already matched the cost of the SCSI2SD V5.1, which is $59.99. Then you'll need to develop the software to use RaSCSI.

If the rascsi works with the Pi Zero though, I have a decent amount of spares of those

 

[PotatoFi]

To me, SCSI2SD already has the storage problem solved. What this project has potential for is to enable ethernet or Wi-Fi connectivity. For SE's and SE/30's, ethernet cards are $150, minimum. A $10 Raspberry Pi, an $8 USB to Ethernet adapter (if you want Ethernet), a $35 RaSCSI board, and a 3D printed internal mount or external enclosure sounds magical (sign me up to design and print those).

And what if you could solve storage and connectivity with one device? Sounds like something @K55 could make money on. But... time. I completely understand the time thing.