• Please review our updated Terms and Rules here

Settings for floppy controller in XT clone

K

kishy

Veteran Member
Joined
Aug 22, 2009
Messages
1,065
Location
Windsor, ON Canada
Hi,

I've obtained a "Conner 2MB Floppy Controller" which is 8 bit ISA. It appears to have a BIOS chip on it and thus may support high density floppies on nonsupporting systems...yay?

That's not the question, however. It has a bank of jumpers, clearly labeled, but I need to know what to set them to. The card is being used in a typical XT clone mobo, no integrated features, but I am using a VGA graphics card.

The floppy card provides these options:

IO Address: 1, 2, 3, 4
IRQ: 3, 4, 5, 6, 7, 9
DMA: 1, 2, 3

Randomly guessing at these settings could take forever and the number of power cycles in quick succession to each other to accomplish that could damage the equipment. Can anyone offer a couple "highly likely to work" combinations for this setup? It does not seek either a 3.5" high density or 5.25" high density drive with no jumpers installed, and my random guess of 3/5/2 (IO, IRQ, DMA respectively) also didn't cause the drives to seek.

Thanks in advance!
 
The default for a floppy controller is IRQ 6 and DMA 2. If this is going to be the computer's primary floppy controller, you should use those settings.

The default I/O address for a floppy controller is 3F0-3F7h. I'm not sure which jumper this maps to on your controller. Perhaps "1" for the primary controller.
 
Is this the half-length card with two headers at the top, one labeled for 2.88MB drives? If so, not only do I have the card, but I think I've also got documentation on it if you get stuck.
 
Chuck(G) said:
If this is replacing your original controller, use I/O address 1, IRQ 6, DMA 2.
Click to expand...

There is no original to speak of, but it will be the only controller. Thanks, I'll give these a try.

vwestlife said:
The default for a floppy controller is IRQ 6 and DMA 2. If this is going to be the computer's primary floppy controller, you should use those settings.

The default I/O address for a floppy controller is 3F0-3F7h. I'm not sure which jumper this maps to on your controller. Perhaps "1" for the primary controller.
Click to expand...

Thanks for confirming it :) Always nice to get multiple people in agreement on something like this, keeps life easier.

Chuck(G) said:
Is this the half-length card with two headers at the top, one labeled for 2.88MB drives? If so, not only do I have the card, but I think I've also got documentation on it if you get stuck.
Click to expand...

Nope, just one header. It's a very tiny card, I'll get pics in here later when I report back with progress. Just says "2MB floppy controller", which I suspect indicates support for high density 3.5" since the "real, unformatted" capacity of one of those disks is approximately 2MB.
 
Alright, so...good news and bad news.

The suggested settings of 1/6/2 work because the first drive seeks after POST. However, it isn't booting from my high density media.

Photo: conner-floppy-controller.jpg

It also isn't booting from a true 720K floppy formatted on my desktop which has a high density drive.

All I own are high density drives...

What's going on here?
 
MikeS said:
http://www.vintage-computer.com/vcforum/archive/index.php/t-16274.html

Sound familiar?
Click to expand...

D'oh!

I Googled the part number and found nothing...figured maybe I stumbled upon a great find. Fortunately it was extra cheap, I won the auction at $0.99 and it shipped USPS First Class so a small loss, if a loss at all.

The thing is, it definitely IS seeking the first floppy drive, and it waits until after the seek to report "boot disk failure". Presumably it is a floppy controller and can be used with floppy media (the silkscreening sure says it can)...just a very picky setup, perhaps?
 
I have a question/point.. DMA? This is an XT.. they don't have DMA... or am I wrong..?
 
Chuck(G) said:
Let's see--pop the top of your 5160. See a 40-pin DIP labeled 8237A (or Am9517A)? That's a DMA controller. 5170s have two of them.
Click to expand...

I read somewhere that the PCjr doesn't have DMA and I thought XT class machines did not either.. I learned something! :p
 
Raven said:
I read somewhere that the PCjr doesn't have DMA and I thought XT class machines did not either.. I learned something! :p
Click to expand...
The original Tandy 1000 series (with the non-standard keyboard that is missing Scroll Lock) also does not have DMA on the motherboard, however if you install Tandy's memory upgrade card, then it includes the DMA chip.
 
Other things to consider at this point are mismatched drive selects... it could be that it sees your floppy as the second drive and can't find a primary.
 
Is it seeking really short? If so it might just be checking the drive, which it would do even if not trying to boot from it. My 5160 has two floppy drives and will only boot from the first one - both seek on boot, however, for a short period.
 
kishy said:
It's seeking the drive though :/
And only the one, the LED on the other one doesn't even come on.
Click to expand...

Kevin, try grabbing a copy of Anadisk and run it in SECTOR mode. See what it sees. Right now, we don't know if it's your drive configuration, the controller or the BIOS.
 
Despite what the silkscreening may indicate, that Conner card is strictly for floppy-interface tape drives. The 2MB denotes the speed, rather than the capacity.

That's why those are so cheap on eBay... they don't work with regular floppy drives.
 
I have some of those tape drives.. and I've been trying to get them to work on normal floppy interfaces (at least I have in the past) to no avail.
 
Old Thrashbarg said:
Despite what the silkscreening may indicate, that Conner card is strictly for floppy-interface tape drives. The 2MB denotes the speed, rather than the capacity.

That's why those are so cheap on eBay... they don't work with regular floppy drives.
Click to expand...

Hmmm, I have a couple of those, but not Conner brand. They actually do use a floppy controller to function, but I've never tried to make one work that way. For one thing, mine have 48 MHz XCOs on i82078 controllers, so coding for them would be a little non-standard. At least one is ISA PnP (16 bit ISA connector, but only an 8-bit data path).

Still, if they're really cheap and plentiful, it might be worthwhile to work out some DOS drivers for them to run floppy drives--if all of the floppy control lines have be brought out to the connector.

Just one of those things I started to check out and never finished.
 
It would be nice if they could be made to work, and it should be doable with a bit of know-how, since it is the same basic interface. However, as you found, there are some issues to address. Actually, I don't even recall the Conner/CTC cards being bootable, though it's been awhile since I've messed with one. (It stands to reason, though... not often you'd want to boot from a backup tape drive.)

As for the tape drives themselves, some of them would work on a regular floppy controller, but they were quite picky at best... they wouldn't work on just any controller. I still have one of the proper Conner drives to match OP's controller, but I never bothered trying it on anything else.
 
You must log in or register to reply here.
Back
Top