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ISA 8-bt SCSI project interest?

Hi Andrew,

The V-USB projects are all device-side, not host-side. Host-side is quite a bit more complicated and all AVR implementations that I've seen of host mode use an AVR-USB chip and a pile of software. For example, here's an app note from Atmel.

Maxim also makes a host controller chip that some have used.

The PIC 24F series also can handle host mode and Microchip has a code example with a pen drive interface.

There are a couple of ARM7 USB host implementations as well as many ARM9 hosts. But everything that I've just discussed is SMT and involves more code than I want to think about.
 
Hi Chuck! A whole bunch of complicated software required and SMT certainly makes it less appealling.

However as you said earlier Vinculum offers a couple of host mode capable DIP packages that would work with the ISA prototype concept. My main reason to avoid SMT for projects like this is many hobbyists are eliminated by using non-DIP construction. Part of my intent for advocating home brew computer is for hobbyists to get involved and build the board themselves! By using SMT in effect, you or me or whomever turns into a board assembly house soldering on the parts for everybody. I don't have time or patience for it so thats a non-starter.

I'll work on the schematics, PCB layout, prototype boards, and manufactured PCBs but not kit assembly or board assembly. I think home brew computer hobbyists have to use the soldering iron (or equivalent) or they are missing something essential.

Thanks and have a nice day!

Andrew Lynch
 
Hi Andrew, I think the Vinculum VDIP1 would be perfect for a hobbyist application in that it fits in a 24 pin DIP socket. The only barrier that I can see is its relatively high price (about $25 from Newark). But this is outside of what I'm willing to do for a simple ISA project.
 
lynchaj said:
Hi! USB on an ISA card is possible. As Chuck said, the Vinculum parts would work on a card like the XT-IDE as would a lesser capable but still USB 1.1 AVR USB
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Yep, thats why I said its probably not worth it to make a whole ISA card to do it. The SCSI idea would be a whole lot more useful. It would be nice to put one of my external JAZ drives onto my XT.
 
Hi! Either the Vinculum VDIP USB ISA project or the SCSI ISA project seem fine to me. From my perspective they seem about the same complexity and effort. I'm willing to help out with a schematic, PCB layout, prototype boards, and manufactured PCBs if/when either or both projects take off.

Actually, I am considering an ISA prototyping board based on the designs posted earlier. They look really handy for projects like this. Basically an 8 bit ISA card with basic buffers, bus transceivers, simple IO decoders, an 8255, and an external port would be tremendously helpful in all sorts of projects.

Thanks and have a nice day!

Andrew Lynch
 
So if somebody wanted to use the Vinculum VDIP for a MFM to USB project they would have to add 128K of SRAM to capture a single track (83K) and also a timer with capture mode? I mean, it would be better for both projects to try to use the same chip if possible?
 
sombunall said:
So if somebody wanted to use the Vinculum VDIP for a MFM to USB project they would have to add 128K of SRAM to capture a single track (83K) and also a timer with capture mode? I mean, it would be better for both projects to try to use the same chip if possible?
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I'm not following you. An MFM controller (or IDE, or pen drive) would be a device-side (i.e. slave) controller. The Vinculum is a host-side (i.e. master) controller. A very different kettle of fish, methinks.
 
Although redesigning an 8-bit ISA SCSI controller would undoubtedly be an interesting and educational project, I would be more interested in the development of an improved version of the XTIDE card with optional DMA and hot-swap/eject support. Reading the XTIDE wiki, it would indeed seem that such features are already planned for revision 2 of the PCB design. Awesome. :) Not only will we not have to start from scratch since we already have a first revision XTIDE design that we can now improve on, the IDE interface is still the most interesting interface to concentrate on, since cheap (< $10 ) IDE converters can already/still be found for CompactFlash, SD, and SATA.

And besides, there are already some 8-bit ISA SCSI controllers out there. The real problem is the lack of proper (ASPI) drivers for them. That is also the case for the Rancho RT1000 card that I really wanted to use with an internal ZIP drive or CDROM player, but couldn't get to work, because the ASPI drivers didn't run on the V30 XT I tried it on. :( So as someone else already proposed here, it would make more sense to develop open source BIOSes and ASPI drivers for the existing models, than to reinvent the wheel outright.
 
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digger said:
And besides, there are already some 8-bit ISA SCSI controllers out there. The real problem is the lack of proper (ASPI) drivers for them. That is also the case for the Rancho RT1000 card that I really wanted to use with an internal ZIP drive or CDROM player, but couldn't get to work, because the ASPI drivers didn't run on the V30 XT I tried it on. :( So as someone else already proposed here, it would make more sense to develop open source BIOSes and ASPI drivers for the existing models, than to reinvent the wheel outright.
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I'm sure you have complete internal documentation for those legacy SCSI cards. You do, don't you? So you can get cracking on an ASPI driver.

8-bit SCSI cards that actually boot larger (8 GB+) hard drives are very uncommon. Do you know of any cheap ones?
 
Chuck(G) said:
I'm sure you have complete internal documentation for those legacy SCSI cards. You do, don't you? So you can get cracking on an ASPI driver.
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You mean the Rancho RT1000 I mentioned? I couldn't find any downloads for that card recently (whether drivers or hardware documentation). At least some years ago, I could still download legacy DOS drivers somewhere. Now, I can't find those anywhere anymore. I did save the drivers I had downloaded back then on a floppy, but it got partially corrupted, so some of the files may have been damaged. :( If anybody can help me with either software or documentation, I would much appreciate it. Perhaps someone knows about a generic ASPI driver that works with most 8-bit SCSI BIOSes out there? That could perhaps also work...?

Oh well... I've but my hope in the XTIDE project now. :)
 
digger said:
If anybody can help me with either software or documentation, I would much appreciate it. Perhaps someone knows about a generic ASPI driver that works with most 8-bit SCSI BIOSes out there? That could perhaps also work...?

Oh well... I've but my hope in the XTIDE project now. :)
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Good luck with Rancho. They sampled us a parallel-to-floppy adapter years ago. They refused to provide any sort of technical documentation, even though there was the prospect of substantial sales if we could get it to work in our application. I still have the adapter and their drivers, but nothing else.

And good luck with getting your DDS or DLT tape drives or your scanner going with the XTIDE.
 
Chuck(G) said:
And good luck with getting your DDS or DLT tape drives or your scanner going with the XTIDE.
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I get your point, but fortunately, that is not going to be an issue for the vintage computer I plan on equipping with an XTIDE card. ;) ...Although it would be an interesting project to get ATAPI tape streamers working with the XTIDE controller, once CD-ROM has been made to work.
 
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