Big Tandy's and HxC Floppy Emulator

[Tibs]

I'm going to construct the cable here in a bit so I can make a few physical floppies.

Do you guys normally just throw it on its own cable using the internal connector? I have two thin lines so I was going to just make a second cable and use the internal cable on the external port to keep things clean while doing this.

I assume I'll need the switch for double sided, I haven't looked to see if the HxC has a method to signal that on some different pins. I was just going to use a toggle switch and write protect the SD card so I dont screw it up, and assume the external port will do the side detections right.

 

[JonB]

I used Mark's adapter board: https://oshpark.com/shared_projects/Hr1FTWxB

..and pulled the jumpers off the internal 8" drive so that the external drive connector could be used without the terminator. Then I jumpered the 8" drive to drive 2, leaving the HxC as drives 0 and 1. Thereafter it is a straightforward matter of making up ribbon connectors with IDC plugs at each end - one 50 way, one 34 way and configuring the adapter board.

 

[Tibs]

I used Mark's adapter board: https://oshpark.com/shared_projects/Hr1FTWxB

..and pulled the jumpers off the internal 8" drive so that the external drive connector could be used without the terminator. Then I jumpered the 8" drive to drive 2, leaving the HxC as drives 0 and 1. Thereafter it is a straightforward matter of making up ribbon connectors with IDC plugs at each end - one 50 way, one 34 way and configuring the adapter board.

Thanks I found that board late last night and I ordered one (well three since thats the minimum).

 

[NF6X]

I'm happy that others are finding my board useful. I have this recurring idea of kludging something to support having an HxC and multiple real floppy drives plugged into a Big Tandy, with a switch to swap the HxC and main internal floppy drive in order to boot from either. I haven't come up with a definition that I like yet, particularly since I'd want it to be useful for either the Model II (1 drive on internal bus, 3 on external) or 12/16(?)/6000 (2 internal, 2 external).

 

[Tibs]

I'm happy that others are finding my board useful. I have this recurring idea of kludging something to support having an HxC and multiple real floppy drives plugged into a Big Tandy, with a switch to swap the HxC and main internal floppy drive in order to boot from either. I haven't come up with a definition that I like yet, particularly since I'd want it to be useful for either the Model II (1 drive on internal bus, 3 on external) or 12/16(?)/6000 (2 internal, 2 external).

Its off to fab, and I was impatient and tried to make a cable from scratch. That ended in frustration. Tried twice. Either I'm blind and cant count across of I've got something else wrong. Its going to be two more weeks for the board to get here.

One question, and I think the answer is yes, the external port is strapped on the same logic as the internal, as in DS1-4 not DS1-2 on both ports like a Model 4?

 

[SteveH]

Thanks I found that board late last night and I ordered one (well three since thats the minimum).

I suspect there are quite a few of us here who have one or two of Mark's adaptors in use and the spare(s) gathering dust somewhere. But the great thing about them is they work in a great range of vintage computers, not just the Tandy's :D

 

[JonB]

I'm happy that others are finding my board useful. I have this recurring idea of kludging something to support having an HxC and multiple real floppy drives plugged into a Big Tandy, with a switch to swap the HxC and main internal floppy drive in order to boot from either. I haven't come up with a definition that I like yet, particularly since I'd want it to be useful for either the Model II (1 drive on internal bus, 3 on external) or 12/16(?)/6000 (2 internal, 2 external).

Hi Mark

How would it switch the internal drive, given that the jumpers on the drive board determine its mapping to the enable signals? You'd have to fit extra leads to the drive's jumpers, no?

Cheers
JonB

 

[NF6X]

Hi Mark

How would it switch the internal drive, given that the jumpers on the drive board determine its mapping to the enable signals? You'd have to fit extra leads to the drive's jumpers, no?

Maybe, but I was thinking that the hypothetical adapter could arbitrarily remap drive IDs as asserted by the host to drive IDs as seen by the drives. I may be overthinking it, though.

 

[JonB]

I think it's only possible if you have the adapter between the floppy controller and the internal drive so that you can rewire the DS0 line.

So. The theoretical adapter could connect to the controller board, and in turn have the internal drive ribbon connecting to its 50 pin output. From then on, all mappings are possible. It would also need a 34 pin output for the HxC or other 34 pin drive.

It's really just a refinement of your existing design.. which makes me wonder if we might use the "unused" lines on the 50 way connector to provide control of the internal drive's DS line. (these lines are currently used by the terminator; you'd have to remove the jumper wires from the drive, too). It might need some modification to the drive PCB (remove the DS jumper, wire it to one of the unused lines, hey presto you can have an external adapter board controlling it).

 

[Hans01]

@JonB

Just bring the drive selection outside the computer.
I use a part of a Shugart SA800 drive PCB as example
Take a 5 position slider or rotating switch and connect it according the picture.
You can disable the drive or let the drive act as drive DS0, DS1, DS2 or DS3

 

[NF6X]

For the systems with two half-height internal drives, I'd consider installing one real drive with an HxC in the other slot, behind a custom trim bezel. I'd put a toggle switch on the custom bezel to swap the two drives in order to boot from either one. It's only on the single-internal-drive systems where I see the need to mess with swapping drives between internal and external busses.

Considering the recent discussion of difficulty formatting new blank image files in the HxC on the big Tandy systems, I naturally wonder whether there would be sufficient interest in a different floppy drive emulator optimized for systems that do non-PC-like things which the HxC and/or Gotek devices don't handle as well.

 

[dittman]

For the systems with two half-height internal drives, I'd consider installing one real drive with an HxC in the other slot, behind a custom trim bezel. I'd put a toggle switch on the custom bezel to swap the two drives in order to boot from either one. It's only on the single-internal-drive systems where I see the need to mess with swapping drives between internal and external busses.

Considering the recent discussion of difficulty formatting new blank image files in the HxC on the big Tandy systems, I naturally wonder whether there would be sufficient interest in a different floppy drive emulator optimized for systems that do non-PC-like things which the HxC and/or Gotek devices don't handle as well.

I would definitely be interested in one that worked with the big systems.

 

[JonB]

@JonB

Just bring the drive selection outside the computer.
I use a part of a Shugart SA800 drive PCB as example
Take a 5 position slider or rotating switch and connect it according the picture.
You can disable the drive or let the drive act as drive DS0, DS1, DS2 or DS3

View attachment 45598

Exactly what I was proposing, except using the proposed new board and connecting those wires to the unused pins on the 50 way connector. Nice picture by the way!

 

[Jeff_HxC2001]

For the systems with two half-height internal drives, I'd consider installing one real drive with an HxC in the other slot, behind a custom trim bezel. I'd put a toggle switch on the custom bezel to swap the two drives in order to boot from either one. It's only on the single-internal-drive systems where I see the need to mess with swapping drives between internal and external busses.

Considering the recent discussion of difficulty formatting new blank image files in the HxC on the big Tandy systems, I naturally wonder whether there would be sufficient interest in a different floppy drive emulator optimized for systems that do non-PC-like things which the HxC and/or Gotek devices don't handle as well.

The HxC is supporting the Model II fine as far i know. What is not "optimized" exactly ?

 

[dittman]

Previously I've tried to format a floppy image on an HxC in my Model II and it's failed. I had the HxC configured as drives 0/A and 1/B. Today I connected the HxC on my Model 12 externally as drives 2/C and 3/D to get the P&T CP/M image (BIOS 2.2m) in the Model II archives copied over (see below for that). After I was done I tried to format the floppy image on the HxC and it worked. It also detected it as a double-sided drive even though I had the DS jumper off on Mark's converter board. I thought that was supposed to make it show as a single-sided drive.

I don't know if this is because I had the drive as an external drive or if it's a difference between the II and 12 floppy controllers. I need to try TRSDOS now.


The P&T drive image is a master that insists on making a copy on another drive. I have P&T CP/M physical floppies for an older version (BIOS 2.2e) but they wouldn't copy the disk image to a physical floppy (C: to B. I also had a couple of physical floppies with 2.2m but they were incomplete and only configured for two drives so I couple back it up (I didn't want to open the 12). I have a physical floppy with Radio Shack CP/M Plus (unbanked-only, unfortunately). I was able to read the HxC image although the DPB wasn't correct so I tried COPYDISK and was able to make a bootable physical floppy. I then booted that floppy and went through the guided creation of a working copy.


As a side note, another one of the floppies I tried to use in the set that came with the Model II flaked off and ruined another floppy, so I've decided that the best way forward is to make images of all the floppies with a Kryoflux or Imagedisk (if I can find a reasonably-priced old motherboard to use with my AHA1542CF) and then toss the old floppies to avoid the temptation of trying to make them work. I have about 70 NIB SSDD and 50 NIB DSDD 8" floppies that I can use instead.

 

[NF6X]

The HxC is supporting the Model II fine as far i know. What is not "optimized" exactly ?

Just some minor things:

Folks are reporting not being able to format a blank image (as opposed to using an existing image of a formatted diskette), apparently because of the different track densities used on track 0 vs. the rest of the tracks. Others have suggested that there's a way to address that, but I'm not clear on the details yet. Even if this isn't just a matter of training the user, it sounds to me like something that could be addressed in firmware on existing HxC hardware.

In terms of hardware, I don't think that the HxC has the means of generating the double-sided detection output which is (usually? always? sometimes?) present in double-sided 8" drives. 8" diskettes have different index hole locations for single-sided vs. double-sided media, and many 8" floppy drives will have index sensors in both positions, and will signal the controller to tell it whether single-sided or double-sided media is inserted. So, it's my understanding that when using the HxC in 8" systems which support both SS and DS media, the user would need to use a switch or jumper on the DS detection line, rather than generating that signal based on what kind of image is being presented by the active emulated drive. And that setting would apply to all drives, limiting the ability to mix SS and DS images (or real floppies) simultaneously in different drives.

There's also the missing TG34 signal present in 8" drives to change write current in tracks above 34, but I don't think it's necessary for an emulator like HxC to see that signal. Even real drives didn't need the signal any more in later designs which were smart enough to count tracks and adjust their write current automatically.

If I was making my own HxC-like emulator with improved 8" drive support, I'd add a 50 pin connector to eliminate the need for an external adapter (keeping the 34-pin connector, of course), I'd add the DS detection output, and while I was at it I'd support all four drive selects. But I'll probably just keep on using my existing HxC units from Lotharek indefinitely without ever finding the motivation to make my own emulator, because HxC is already 98% perfect.

 

[JonB]

I've had the same problems with mine - solution was to copy a disk image several times, renaming BLANK_01, BLANK_02 (etc). Then, when I want a blank formatted disk select one (on the HxC) and do ERA *.* (in CP/M).

A pain, but workable.



*** Slightly off topic - apologies ***

However, since using Hans01's LoTech IDE adapter adapter (not a typo!) I have been booting off the HxC to Lifeboat CP/M on a DOM and it's been brilliant. I don't really use floppies now..

If you're using P&T CP/M the device isn't supported, though. Someone really should write some P&T IDE drivers... cough, cough..

 

[dittman]

I've had the same problems with mine - solution was to copy a disk image several times, renaming BLANK_01, BLANK_02 (etc). Then, when I want a blank formatted disk select one (on the HxC) and do ERA *.* (in CP/M).

A pain, but workable.



*** Slightly off topic - apologies ***

However, since using Hans01's LoTech IDE adapter adapter (not a typo!) I have been booting off the HxC to Lifeboat CP/M on a DOM and it's been brilliant. I don't really use floppies now..

If you're using P&T CP/M the device isn't supported, though. Someone really should write some P&T IDE drivers... cough, cough..

The problem I was running into with the P&T master floppy from the Model II archive was that it insisted on making a copy when booted so I couldn't use the HxC as the second drive since the copy program insisted on formatting the destination so I had to use a real floppy since the format failed.

What was surprising was after booting from the newly created floppy I could format the disk image on the HxC (set as drive C/2). I need to play with it some more. I want to try mounting another image as drive D/3 and see if I can format it. I've had some odd issues with the second emulated drive on the HxC on some other systems like my Ampro LittleBoard.

 

[Tibs]

The problem I was running into with the P&T master floppy from the Model II archive was that it insisted on making a copy when booted so I couldn't use the HxC as the second drive since the copy program insisted on formatting the destination so I had to use a real floppy since the format failed.

What was surprising was after booting from the newly created floppy I could format the disk image on the HxC (set as drive C/2). I need to play with it some more. I want to try mounting another image as drive D/3 and see if I can format it. I've had some odd issues with the second emulated drive on the HxC on some other systems like my Ampro LittleBoard.

So last night I was building the 52 Font Disks for DotWriter (Yeah, I have all 52 woo hoo). I noticed that my blank image folder had four files named as so:

40TSSDD <- I use this on the Model III/4 almost exclusielvey.
40TDSDD <- I use this rarely.
35TSSSD <- Model I software almost always came on this format
35TSSMD <- Model I Mixed Density - I used a copy of either TRSDOS 2.8 or LDOS Soled).
77TSSDD <- I haven't used this yet, but Its there
77TDSDD <- I haven't used this yet, but its there.
80TDSDD <- Backing up hard drives.

So, I would expect if we were to get a master of the right disk, convert it to HFE, then just copy it every time we wanted a blank image that would solve the TRSDOS problem on the Model II/12/16/6000s

I know I was able to do this last night it worked great.

I do however have a working copy of PowerTool (This was a SuperUtility program that was stripped down) and cant because the way the program creates the disk is it formats in both densities all over the place. It would take a Flux reader to create an image that works in the HxC.

I do agree with Mark, this could be fixed, and they were talking about doing that, in firmware. I'd like to see a LDOS/LSDOS command that lets us navigate the menu of software like the DOS one does, but I have not looked the source to see if its possible on the TRS-80 to do what they do.

 

[Tibs]

Ok, Boards came in today and with it connected, the converted IMGs to HFE seek, but cant read them at all. I was kind of hoping to at least be able to backup a 2.0B disk to a blank floppy. I keep getting drive not ready errors (error 08)

Are there certain settings for the drive type and image type that have to be set inside the emulator software? Things like drive type, pin 34 and pin 2 are customizable but I always used auto/read from HFE.