Connect HxC to A1200 External Floppy Port

[stevendt]

Hi,

I am new to the Amiga, but would like to connect HxC to the external floppy port of my "new" A1200.

Apart from the fact that the Amiga has a 23 way D connector, can someone tell me how to connect HxC to the floppy port? For example, if I get an old Amiga floppy cable, can I just connect it to HxC?

The crucial question is probably whether the Amiga expects to see a standard Shugart floppy disk interface, or is any special wiring required?

regards
Dave

[Arnie]

I used an old external floppy drive and replaced the drive with the HXC (SLIM). It works O.K but I could only use one of the emulated drives, DF1:, DF2: wouldn't show up.

[stevendt]

Hi Arne,

thanks for the info.

Has anyone got a way of keeping the internal floppy and using HxC as DF1 and DF2?

regards
Dave

[Jeff]

Hi Arne,

thanks for the info.

Has anyone got a way of keeping the internal floppy and using HxC as DF1 and DF2?

regards
Dave

Just use the right external interface and the switch setting. This is just a DSx lines story.

[stevendt]

Hi Jeff,

thanks for the reply, a couple of questions though please . . . .

You said "This is just a DSx lines story."

The HxC manual says "Unlike real floppy disk drive the SDCard HxC Floppy Emulator doesn't use the motor control line. So there are only one jumper to set per virtual disk drive. "

Atari ST / Amiga / Shugart jumper settings
ID line ID3 ID2 ID1 ID0
Host Line MTRON DS2 DS1 DS0
Function Motor On DF2 B: / DF1 A: / DF0

Can you explain what the MTRON entry in the table means ?

When you say, "Just use the right external interface ...... "
What did you mean by that?
I think that the Amiga needs Shugart Pin 34 (Disk Change) wired to Amiga pin 2 - that is easy enough
But, I think that the Amiga also needs to see a separate "Ready" signal on Pin 34 - how is that generated ?

regards
Dave

Hi Arne,

thanks for the info.

Has anyone got a way of keeping the internal floppy and using HxC as DF1 and DF2?

regards
Dave

Just use the right external interface and the switch setting. This is just a DSx lines story.

[Jeff]

Can you explain what the MTRON entry in the table means ?

This is the line number 16 :
http://pinouts.ru/Storage/InternalDisk_pinout.shtml

Generaly use to switch on the main motor to rotate the disk.

When you say, "Just use the right external interface ...... "
What did you mean by that?

What i mean is that many external Amiga floppy disk drive board seems to have a strange design. I can't say on which DSx lines they are connected and how this signals are redirected to the floppy drive. You need to find this yourself (with a continuity tester for example...)

I think that the Amiga needs Shugart Pin 34 (Disk Change) wired to Amiga pin 2 - that is easy enough
But, I think that the Amiga also needs to see a separate "Ready" signal on Pin 34 - how is that generated ?

The HxC emulate these signals properly himself.

[gonk23]

What i mean is that many external Amiga floppy disk drive board seems to have a strange design. I can't say on which DSx lines they are connected and how this signals are redirected to the floppy drive. You need to find this yourself (with a continuity tester for example...)

I believe most external Amiga floppy drives are configured to connect pin 21 (/SEL1) of the input DB23 connector to pin 10 (/DS0) of the IDC34 connector. Now, external drives with passthrough connectors will normally connect pin 9 (/SEL2) of the input DB23 connector to pin 21 (/SEL1) of the output (passthrough) DB23 connector. Also pin 20 (/SEL3) of the input DB23 connector is connected to pin 9 (/SEL2) of the output (passthrough) DB23 connector. This simple but clever design allows external drives to be daisy chained and respond as DF1, DF2, and DF3 without needing to configure DIP switches on the drives.

But this probably means that pin 9 (/SEL2) of the input DB23 connector isn't connected to pin 12 (/DS1) of the IDC34 connector, and is probably why the HxC's 2nd virtual drive doesn't respond when the HxC is connected to an external drive interface. The external drive interface will need to be rewired.

[gonk23]

The diagram at the end of the following (http://www.ianstedman.co.uk/Amiga/desig ... or_v2.html) might be what you're after (there's no need to read the whole page). It connects both /SEL1 and /SEL2 select lines to the corresponding Shugart /DS0 and /DS1 pins.

[Arnie]

so what you are saying is that it's best to use a straight through cable and leave out the external board altogether.

[gonk23]

so what you are saying is that it's best to use a straight through cable and leave out the external board altogether.

Not necessarily. I provided that link mainly as a reference on how the lines might be connected (@stevendt asked for that in his original post).

Like you, I use an old external drive with the floppy drive removed because it's convenient to have both the data and power plugs already made-up. I haven't had the need to use DF2: however I might have a closer look to see if it's easy to modify it to use the extra drive select signal (although I won't be able to have a look for another week or two because I don't have my amiga gear at hand at the moment).

[Arnie]

My External drive case has a pass through for DF2:. I'm wondering if it's possible to hack this to gain the extra drive.

And yes, it is handy to have all the connections ready to use. I'm currently using a rev F HXC (great piece of kit) and it would be nice to have an extra drive but, not essential.

[gonk23]

To enable DF2: on an existing external drive PCB, you can connect pin 9 (/SEL2) of the input DB23 connector to pin 12 (/DS1) of the IDC34 connector. I tried this and it works great, i.e. I get both drives on my HxC. I soldered a wire between the appropriate pins on the PCB. However I don't recommend using the pass through connector after doing this because potentially 2 drives will be connected to the /SEL2 signal.

[gonk23]

I notice that using 2 virtual drives on the one HxC can be a bit weird. For example, when I select the drive (A/B) or a disk image using the HxC, it actually ejects both disks and then remounts them. This might cause problems if you're formatting/copying a disk image in one virtual drive and try selecting a different image on the other virtual drive -- i.e. the formatting/copying will be interrupted as if you had also ejected that disk. I believe this is due to HxC processor limitations, i.e. it cannot handle UI input and disk operations at the same time. In a lot of cases it doesn't matter, but if you need true independent virtual drive operation then you're better off buying a 2nd HxC.