Hacks & Development
RaSCSI Development Thread
By K55,
May 3, 2017 in Hacks & Development
cheesestraws
Location England & Wales
14 hours ago, Byte Knight said:
Nice! It would be awesome to have Ethernet functionality too.
The fun thing here is because it's a tap interface, you can run other software on the r-pi directly plugged into that "network". So, for example, you could bridge the tap interface to a wireless interface and add a bit of code to configure the wireless either through a web UI or by broadcasting the SSIDs you can see via NBP and writing a little Chooser extension to switch between them (which I think is probably the most System 7-idiomatic way of doing it)
landoGriffin 115 posts
cheesestraws 29 posts
NF_ 25 posts
Trash80toHP_Mini 22 posts
landoGriffin
Location Cedar Rapids, IA
Making some progress on Ethernet support! Its turning out to be much more complex than I originally hoped. The original RaSCSI code didn't have "Reselection" capability, which the Nuvolink SC uses. RaSCSI was developed assuming that the host would ALWAYS initiate the communication. That doesn't work well if you're receiving network packets and need to push them to the host.
Also - I put up a handful more RaSCSIs on Tindie, for folks who are waiting for one. There's only one left, but I should have more in a couple weeks.
Also - join us on Discord if you want to talk more about RaSCSI! https://discord.gg/PyS58u6
They're back in stock!!!
https://www.tindie.com/products/landogriffin/rascsi-macintosh-version/
Promo code for my 68kmla buddies through Sunday: THEYREBACK for $10 off.
PotatoFi
Location Boise, ID
14 hours ago, landoGriffin said:
Promo code for my 68kmla buddies through Sunday: THEYREBACK for $10 off.
Excellent news! And to celebrate, I'm going to attempt to solder one of these together. Live. In front of people. What could possibly go wrong?
Details here:
Edited October 7, 2020 by PotatoFi
On 10/7/2020 at 3:09 PM, landoGriffin said:
They're back in stock!!! 
https://www.tindie.com/products/landogriffin/rascsi-macintosh-version/ 
Yes! I missed the last batch, ordered one of these...
Endsjustify
It's an easy and fun build of an endlessly useful tool. I can't suggest Picking this kit up enough. I've used mine almost every day since build.
11 hours ago, Endsjustify said:
So glad to hear that!! I would love to see some action shots to see how people are using it!
My hubby made a IIci style box for my Pi zero Rascsi!
8 hours ago, landoGriffin said:
@PotatoFi is live-streaming an assembly right now!
quorten
Location Minneapolis, MN, USA
I'd have to say, I think @PotatoFi's video (I wasn't on the livestream) is pretty good to watch for those of us who question our soldering skills... I guess I'm actually not too bad for a novice myself after all. Otherwise, yeah, with the length and all, sort of a waste of time to watch the whole thing, but hey, PotatoFi had to go through all of that time one way or another.
16 hours ago, quorten said:
It was intended to be more about "hang out" time than an instructional video. I personally can't watch recorded live streams after the fact - something about watching it happen live is entertaining, but when it's done, I'm just not interested.
And if I can solder one of those up, anybody can!
16 hours ago, PotatoFi said:
It was intended to be more about "hang out" time than an instructional video.
Yeah, really, I agree... I figured it would be a good idea to find out what the hangout time was like after the fact since I missed it live.
Edited October 12, 2020 by quorten
A couple comments about a post that @Byte Knight made in the MacSD thread....
I've got a RaSCSI too ..... but it's nice not having to wait for the Pi to boot up before you turn your computer on....
If you don't have any other bootable drives installed, the Mac will wait for RaSCSI to boot up. So, you might see a flashing question mark for 10-20 seconds. But, the Mac should boot once RaSCSI starts up.
and it's also nice to be able to hook up an HD activity light.
RaSCSI has that too. I didn't get around to testing it until a few days ago, so I hadn't been advertising it. Next to the ACT/ENB LEDs there are two holes for a header. You can hook up an external LED with a little dab of solder and a couple header pins. (They could go on the top OR bottom - doesn't really matter)
Byte Knight
Location Waconia, MN
I stand corrected - thanks for clarifying!
On 9/5/2020 at 12:59 PM, landoGriffin said:
As-is, No. I don't think it would be possible. The Parallel port pinout is quite different from the SCSI pinout.
Well I was looking at this further and the RaSCSI bus transceivers are compatible, very similar to the first design of pi-parport actually. So really all that's needed is to add a few switches/transistors to change the bus termination resistors and an external dongle to rewire the pinout on the DB25 connector. Finally the pi-parport drivers can be dropped in verbatim simply by using a different ID EEPROM on the RaSCSI board, this will load a different DT Overlay with the different pinout and it will all just work.
At least that's my cursory assessment. It would be nice to have one board that can do it all. Oh, and I didn't mention that you can make a parallel port board that can act either as a "host" or a "device." That would obviate the need for some of those proprietary Raspberry Pi boards meant to emulate a parallel port printer.
EDIT: On the question of ESD protection diodes, the existing bus tranceivers probably already have them (on a continuity check, GPIO-side pins appear to be all shorted to ground when the chip is powered off), but it could be that parallel port transceivers are designed with better ESD protection. It might be worth considering if better ESD protection is desirable for a SCSI interface too.
ESD protection diodes
Hello, cyber pals.
I've been recording a series of videos on C Programming on System 6 using a camera (iPad) in front of my Mac 512Ke/Plus. After reading about the ScuzzyView device, I figured it should be possible to make something similar that sends the screen buffer over the SCSI port and turn it into a video stream that I can capture, which led me to the RaSCSI.
This weekend I started working on it and was able to send the screen data through RaSCSI and turn it into an XBM image to display on my laptop. Then I got live screen mirroring working by having RaSCSI draw the data stream onto the framebuffer of the Raspberry Pi.
I plan on upstreaming my changes to RaSCSI once it's in a better state, and maybe support things like recording the data to a local file rather than forcing it onto the framebuffer and supporting color/non-1bpp data. For now, my changes are available in my "video" branch:
https://github.com/jcs/RASCSI/commits/video
I will also be releasing the code to the Mac program which sends the screen data through the SCSI Manager. Right now it's implemented as a normal application so it only mirrors while it's the foreground application. It needs to be changed to act as a driver so it can run all the time.
3 minutes ago, jcs said:
This is really cool.
17 minutes ago, cheesestraws said:
I second that! This is awesome!
59 minutes ago, jcs said:
Right now it's implemented as a normal application so it only mirrors while it's the foreground application. It needs to be changed to act as a driver so it can run all the time.
Are you sure it needs to be a driver to run all the time? Both the Process Manager under System 7 and later, and MultiFinder on System 6 include provision for background application processing.
Agreed, this is really cool!
Dog cow is correct above, but if you want it to run on a Plus running pre-System 6 or pre-MultiFinder (which would be cool), you'll indeed need to write it as a DRVR (or maybe even as a VBL task?).
Michael_b
That's awesome! How much of a leap is it from this to something like the SCSIgraph? I assume it would be a matter of having a second (virtual) display that the Mac thinks is connected, and having a screen buffer for that display available to be copied over SCSI?
It looks like the SCSIgraph also had color output - maybe this could be part of a solution to obtain grayscale video on the SE/30 (or earlier) without an XCEED card...
At the outset, the idea sounds awesome! Of course, as you've mentioned, there's still plenty of work to be done on the implementation. A proper video driver interface, like used by the old PDS video expansion cards, would expose drawing commands that would be hardware accelerated, and that would definitely improve the framerate on the Raspberry Pi side.
4 hours ago, Michael_b said:
Ha! I wonder as well if I could use a SCSI device to accelerate 3D graphics as well – I'd block transfer vertices and transformations in, rasterize on the RaSCSI, and read a framebuffer out...
Edited October 26, 2020 by rplacd
superjer2000
On 10/25/2020 at 11:35 AM, jcs said:
I hadn't seen any references to the C programming videos you are doing - that's a great initiative! I had started trying to learn toolbox programming using C on the mac a while ago and put it down but plan to get back into it and will be sure to check these out. Thanks! (And obviously the RAscsi hack is incredible!)
Phazmatis
Threw together a minimal version of the board, just two headers and the 4 chips (no on-board termination). Hope I didn't make any mistakes, and OSHPark likes it, and I didn't miss an important component. https://oshpark.com/shared_projects/FLWSmnqS (Board file / schematic is here, but I don't think anyone uses CircuitMaker haha https://workspace.circuitmaker.com/Projects/Details/Edward-Halferty/rascsi )