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Old 05 February 2018, 12:01   #1
CBMFreak
 
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Smile Drive ID selection on external drives using cables

As the title suggests... I am looking to select ID's of external drives, hopefully just by using additional cables...

I would like to place my hxc slim inside my A1200 as DF0 + DF1 ...
I am currently using a GOTEK inside my A1200....

then I would like to connect one external floppy drive as DF2 ...
and my GOTEK with Cortex firmware as DF3 ... The idea is ... to use this information to make intermediate cables
to a "common" remote amiga floppy drive thus ...
http://ianstedman.co.uk/Amiga/design...daptor_v2.html

Amiga 1200 -> intermediate cable that sets next device to DF2 -> Amiga Ext Floppy -> intermediate cable that sets next device to DF3 -> Amiga Ext Gotek Adapter Curcuit board -> Gotek Is it possible? Can Gotek drive use pre-configured USB sticks,
possibly just throwing an ADF on there named after that file it usually default boots? Can the GOTEK drive setup ADF file determine if the
GOTEK drive is not DF0 and if it is not the boot drive? Can I configure a USB stick to a GOTEK drive on a PC
without involving the amiga? What are the possibilities and how much can be done? I have a SUM USB in the machine and a USB card reader that
I am considering using the card reader's USB port
for SUM USB and replacing the card reader's PCB with my HxC Slim Alternatively, I'll build both hxc (df0 + 1) and gotek (df0)
into the card reader and make a switch that switches
between the two ...
 
Old 05 February 2018, 15:01   #2
Daedalus
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It's normal for an external drive to shift all the select signals down one as it passes the signals through. Each drive responds to the same select signal, and then passes the next select signal through to the next drive as the first select signal. So, the first external floppy responds to _SEL1, and the passthrough within that floppy unit sets _SEL2 to _SEL1 and _SEL3 to _SEL2. That scheme is already there for external floppies, it should be no different for external Goteks, so you can make DF2: the first external drive by simply connecting _SEL2 to _SEL1 and _SEL3 to _SEL2.

Bear in mind however that there is a little extra logic used to latch signals in external drive units, and the Goteks will similarly require this.
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Old 06 February 2018, 09:36   #3
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Quote:
Originally Posted by Daedalus View Post
It's normal for an external drive to shift all the select signals down one as it passes the signals through. Each drive responds to the same select signal, and then passes the next select signal through to the next drive as the first select signal. So, the first external floppy responds to _SEL1, and the passthrough within that floppy unit sets _SEL2 to _SEL1 and _SEL3 to _SEL2. That scheme is already there for external floppies, it should be no different for external Goteks, so you can make DF2: the first external drive by simply connecting _SEL2 to _SEL1 and _SEL3 to _SEL2.

Bear in mind however that there is a little extra logic used to latch signals in external drive units, and the Goteks will similarly require this.

Ok thanks.. so simply making (a) cable(s) that swaps signals is not enough? any links on how to build additional required curcuits?
 
Old 06 February 2018, 10:05   #4
Daedalus
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Sorry, I'm re-reading this now... I got the impression you wanted a single chain of drives, but if you want the first drive attached to the external port to be DF2, it can't be done without modifying it, its cable or the motherboard.

The logic should be easy enough to find as it's fairly standard in any external floppy drive unit. I don't have it here myself however, but I'll look later on if I get a chance.
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Old 12 February 2018, 10:42   #5
CBMFreak
 
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Smile Amiga drive chain

Quote:
Originally Posted by Daedalus View Post
Sorry, I'm re-reading this now... I got the impression you wanted a single chain of drives, but if you want the first drive attached to the external port to be DF2, it can't be done without modifying it, its cable or the motherboard.

The logic should be easy enough to find as it's fairly standard in any external floppy drive unit. I don't have it here myself however, but I'll look later on if I get a chance.
I want to create a cable (or rather.. 2 cables) to put between the Amiga and an external drive unit

the first cable (cable1) should force the first external drive unit to become DF2, such that my internal HxC can occupy DF0+DF1

then I could have HxC as DF0+1 and an ext floppy drive as DF2

then I want to create a second cable (cable2) to be used between the external floppy drive and an external Gotek to force the Gotek to become DF3...

I might, if this is possible.. have to settle for only being able to use a single ADF file (boot.adf) per USB device in the Gotek, but it would still be useful!

The external Gotek will consist of a gotek external adaptor logic board and a gotek... I have the Amiga, the Hxc, the Ext floppy drive, the Gotek and the req ext logic board

So the whole thing would be...

A1200 /w HxC --- Cable1 --- ext floppy --- Cable2 --- ext Gotek

Is this at all possible?
 
Old 12 February 2018, 11:03   #6
hooverphonique
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If you just use SEL2 on the amiga floppy port and connect this to SEL0 of the first external drive, it will become DF2, but I think the amiga will skip looking for DF2 if DF1 isn't present, so you need DF1 to be present internally at the same time (DF0 is always assumed to be present).
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Old 12 February 2018, 11:08   #7
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Quote:
Originally Posted by CBMFreak View Post
I want to create a cable (or rather.. 2 cables) to put between the Amiga and an external drive unit

the first cable (cable1) should force the first external drive unit to become DF2, such that my internal HxC can occupy DF0+DF1

then I could have HxC as DF0+1 and an ext floppy drive as DF2
Two options here.

1) modify an existing external drive, get one which has a D connector you can take apart. Identify SEL1, SEL2, SEL3 at the D connector, write down which colour wire goes to which. Then you will have three wires: 1, 2, 3. Now connect the 1 wire to the SEL2 pin on the D connector and the 2 wire to the SEL3 pin. The #3 wire will be left disconnected, tape the end so it doesn't touch anything and reassemble the D connector shell.

2) make a D23 -> D23 cable that connects everything but the selects straight through, then do the same trick with the drive selects there.

http://old.pinouts.ru/HD/ExtDiskAmiga_pinout.shtml

I'm so lazy that I'd definitely go with 1) and just write a note on the bottom of the external drive saying that it skips a select.

Quote:
then I want to create a second cable (cable2) to be used between the external floppy drive and an external Gotek to force the Gotek to become DF3...
You do not need this second cable. The external floppy drive's logic board does the shifting for you. Anything you plug into its daisy chain port will automatically be the next drive.

Quote:
A1200 /w HxC --- Cable1 --- ext floppy --- Cable2 --- ext Gotek

Is this at all possible?
Yes. Internally you will need Stedy's drive adapter board between the drive which is to be DF1 and the floppy cable. Or the equivalent motor latch/id stream board you have made yourself or removed from an old external drive. In an A1200, SEL1 is already available at the internal floppy port, but the logic is not. You will also need to pick up the motor signal for your internal DF1 with a jump lead/test clip from the external floppy port or the 74LS86 at U26. The signal name is MTRX for non-DF0 drives.

Quote:
Originally Posted by hooverphonique View Post
I think the amiga will skip looking for DF2 if DF1 isn't present, so you need DF1 to be present internally at the same time (DF0 is always assumed to be present).
Big box machines reserve SEL1 for the internal connector and the first external drive will be DF2 regardless of how many internal drives you actually have. Trackdisk.device handles this fine, no ROM patches needed. :-)

Last edited by Jope; 12 February 2018 at 11:34.
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Old 13 February 2018, 09:25   #8
CBMFreak
 
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Thanks for the information and help everybody, I will go with option 2, so that the internal HxC can have DF0 and DF1 all to itself and leave DF2 and DF3 to the external drives :-)

I hope that the HxC will continue to work fine internally as DF0 and DF1 as before despite an altering of the select signals on the ext floppy connector.

Its good to know that I only need to do one cable :-)
 
 


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