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RickNel
December 21st, 2010, 02:32 PM
Has anyone interfaced a LS-120 "superfloppy" drive to a S-100 system?

I have one with a parallel port interface that appears on PC systems as a SCSI drive.

My vintage s-100 system is floppy-only - no IDE or SCSI interface.

Could a LS-120 interface be set up just in a BIOS modification + software?

I'm thinking at least some kind of generic SCSI interface board might be needed to cope with the high-speed transfers, subject to limitations of a 4Mb Z80 CPU.

Or can LS-120 masquerade as a FDD driveable by a uPD765 controller?

Just wondering...

Rick

Chuck(G)
December 21st, 2010, 03:14 PM
Of course you can interface a parallel LS-120 drive to an S-100 system--just write the necessary driver software. The command set for all LS-120 drives is basically SCSI (ATAPI is at its core, the SCSI command set embedded in ATA packets). The transfer speed has little to do with the implementation as the LS120 is buffered internally.

Your only task is to figure out the handshake protocol--it's entirely possible that someone's done the work for you in the form of a Linux driver.

NobodyIsHere
December 21st, 2010, 03:58 PM
Hi! You could connect the LS-120 to the S100computers.com & N8VEM S-100 IDE board. The LS-120 is an IDE device -- ATAPI actually. The hard part will be writing the software although you could reuse the N8VEM DiskIO IDE & ATAPI code. It is found on the N8VEM wiki.

I hope this helps! Thanks and have a nice day!

Andrew Lynch

PS, John and I are considering an S-100 SCSI board based on a modified S-100 ZFDC. Basically it would be similar with a Z80 based embedded controller interfaced to a SCSI controller (Z53C80 for instance). Then the S-100 CPU board would communicate with the S-100 SCSI controller with a high level protocol similar to how the S-100 ZFDC works now.

Chuck(G)
December 21st, 2010, 05:03 PM
Hi! You could connect the LS-120 to the S100computers.com & N8VEM S-100 IDE board. The LS-120 is an IDE device -- ATAPI actually. The hard part will be writing the software although you could reuse the N8VEM DiskIO IDE & ATAPI code. It is found on the N8VEM wiki.

Well, the LS120 did come in a parallel version, but fortunately, the parallel part can be removed to get to a more-or-less standard EIDE drive:

http://www.itnetcentral.com/tech/convert-your-ls120-205.html

If you were trying to interface to a simple 8-bit parallel port, I'd keep the parallel adapter intact, however. I doubt that speed would be a consideration.

RickNel
December 22nd, 2010, 08:39 PM
Thanks for suggestions. If a software-only solution is possible without hardware mods, that would be my preference.

An 8-bit parallel port driver would suit best. I'll hunt around Linux sites.

Given that the LS-120 was developed well into the 16-bit era, I'd expect most drivers will be for 16-bit systems.
If an 8-bit parallel driver can be put together, then the device could be a handy shared storage between S-100 and PC-based systems or emulations.

Another project for the to-do list...

NobodyIsHere
December 23rd, 2010, 03:25 AM
Hi Rick!
Whatever you decide to do please keep us updated on this thread and post some pictures! I am curious to see how this will work out. I seem to remember that some builder was able to use the N8VEM DiskIO to boot from either an LS-120 or Zip drive which were both ATAPI devices. It required a special boot ROM but it suggests what you are proposing is certainly possible. How difficult is another matter...

If you want to go straight to the parallel port that is certainly possible. It will require a custom parallel interface though. What S-100 boards do you have available with a generic 8 bit parallel port with control signals? I've seen PC printer parallel ports implemented with only 16 GPIO pins with a (nearly) full complement of data and control signals.

Thanks and have a nice day!

Andrew Lynch

RickNel
December 27th, 2010, 01:49 PM
Andrew - my i/O board is an IMS 440. The parallel device is 8255A, programmable and with some on-board mode settings via jumpers, with options for 3 x 8-bit ports or other configurations of the 24 available bits. I think it is referenced on John Monahan's s-100 board pages. My documentation PDF for the board is too large to attach here, but if you are interested I can upload it somewhere else for you.

The parallel port is not currently used for any other function on my system - printer is TTY on serial 2.

I wasn't thinking particularly of using the LS-120 as boot device, but that could be explored as an option. The standard IMS boot ROM searched all known devices for a boot sector, but I have stripped that from my current ROM to make space for monitor functions. It could be restored.

Happy New Year to all..

Rick