External Disk Drive As Main Drive?

[troed]

I've now begun actually modifying my STE and am about to make the A<->B switch. I'll go for the non-leg cutting/bending method on the wiki since my sound chip isn't socketed.

However, having studied the schematics I'm confused as to the comments on DS0/DS1 being available on the external connector. As far as I can see it's an easy modification to make it so - but it's not the case by default. I'm probably in the wrong though - I'm a software guy pretending to understand micro electronics, but I'd like to know what I'm missing.

Look at the attached schematics. If W300 had been linked 1-2 DS1 would indeed be available on the external pin 6 - but I can't see how it is now (and the schematics match my STE).

(DS0 is always available on the internal pin 10. DS1 is always available on the internal pin 12. DS1 is available on the external pin 5 since W301 is linked 2-3. If it had been linked 1-2 instead DS0 would be available on pin 5. Modifying both W301 and W300 would thus make the external port include DS0 and DS1 just as on the internal port)

[img]ste_ds0_ds1.png[/img]

[Jeff_HxC2001]

W300: Disable or enable the DS1 output on the second external drive select output. (Default : disable).
W301: Select DS0 or DS1 as output on the first external drive select output. (Default : DS1)

These straps are there to put all drives outside of the ST (as the 260ST...)

[troed]

W300: Disable or enable the DS1 output on the second external drive select output. (Default : disable).
W301: Select DS0 or DS1 as output on the first external drive select output. (Default : DS1)

These straps are there to put all drives outside of the ST (as the 260ST...)

Thanks Jeff Then I'll continue to trust my schematics-reading skills (as I see Dal also did earlier in the thread). The pinout at http://info-coach.fr/atari/hardware/int ... _Connector is thus valid for 260/520ST, only, but not STF or STE models (by default).

Question: Is it possible to connect both the internal floppy as well as an HxC to the internal cable - since it has both DS-signals available and Motor isn't needed for the HxC? A non-twisted flat cable with dual connectors seem reasonable to use if the HxC is configured as drive B. Although all suggestions I've seen have so far mention creating a new cable connecting to the external port I haven't understood why, yet.

edit: Of course, with the intention of adding a switch that simply swaps DS0/DS1 at pin 10/12 then.

/Troed

[Jeff_HxC2001]

W300: Disable or enable the DS1 output on the second external drive select output. (Default : disable).
W301: Select DS0 or DS1 as output on the first external drive select output. (Default : DS1)

These straps are there to put all drives outside of the ST (as the 260ST...)

Thanks Jeff Then I'll continue to trust my schematics-reading skills (as I see Dal also did earlier in the thread). The pinout at http://info-coach.fr/atari/hardware/int ... _Connector is thus valid for 260/520ST, only, but not STF or STE models (by default).

Yes. To keep some kind of compatibility with the old external drive with the new STF,STE machines, the external DS0 line was connected to the internal DS1 line to avoid conflit with the internal drive (on DS0). That's the purpose of W300 & W301

Question: Is it possible to connect both the internal floppy as well as an HxC to the internal cable - since it has both DS-signals available and Motor isn't needed for the HxC? A non-twisted flat cable with dual connectors seem reasonable to use if the HxC is configured as drive B. Although all suggestions I've seen have so far mention creating a new cable connecting to the external port I haven't understood why, yet.

I see no problem at all to do this. i have done this myself several times.

[troed]

Question: Is it possible to connect both the internal floppy as well as an HxC to the internal cable - since it has both DS-signals available and Motor isn't needed for the HxC? A non-twisted flat cable with dual connectors seem reasonable to use if the HxC is configured as drive B. Although all suggestions I've seen have so far mention creating a new cable connecting to the external port I haven't understood why, yet.

I see no problem at all to do this. i have done this myself several times.

Thanks - it's definitely my preferred method of installing the HxC keeping the original disk drive then. However, I'm failing, and I don't understand why. As described above all that's needed is a straight 34 pin cable with two connectors - and I've just built two of them from regular "PC" floppy cables. One by cutting and re-attaching the second IDC connector (image included) and another by keeping all the existing connectors - just un-twisting the twist at one of them.

However - no matter what I do (and I've tested attaching just the HxC, or the original drive) as soon as I add my new cables the floppy/HxC is not recognized. When trying to boot off the HxC the STE actually displays four bombs after the memory test.

My only hypothesis at the moment is that the use of a gender changer to add the new cable causes too much resistance for the STE to drive the signals - but as I wrote above; I'm a software guy pretending to understand electronics All pins measured and re-measured, all connect, no cross-talk. I don't test with the cable connected upside-down either

Any thoughts? Image of cable with gender changer attached.

DSC_0514.JPG

/Troed

[Hippy Dave]

The cable may be too long.
Use as few cables and devices as possible.
Try to put the gender changer as close as possible to one end of the cable.

[troed]

Thanks - it's definitely my preferred method of installing the HxC keeping the original disk drive then. However, I'm failing, and I don't understand why.

...

Any thoughts? Image of cable with gender changer attached.

This has now been solved. It took me far too long to figure out that just using a male-male gender changer between two floppy cables would invert the rows. I documented the one-wire fix you can make to the extender-cable in a thread here: viewtopic.php?f=15&t=19006#p256502

I now have both the internal drive (A:) and HxC (B:*) hooked up in my STE. Works a treat.

/Troed

*) Although the jumper setting I thought I should use on the HxC, ID1/Drive B wasn't correct - jumpering as ID1/Drive A works though, as B:. The cable is not twisted.

hxc_jumper.jpg

[DrCoolZic]

The pinout at http://info-coach.fr/atari/hardware/int ... _Connector is thus valid for 260/520ST, only, but not STF or STE models (by default).
/Troed

I will post more info on this thread ...
But before I forget I have updated my documentation at http://info-coach.fr/atari/hardware/int ... _Connector
It should now correctly describe the drive selction based on Atari model and straps setting.

[DrCoolZic]

1. Pin 8 from the Atari's 14Pin External FDD connector is motor On. is is correct that I will need to wire a switch at my HxC in order to flick this signal between Pin 10 (MOTEA) for Drive 0 and Pin 16 (MOTEB) for Drive 1?

You have to be careful. Atari uses the original Shugart pinout and not the PC pinout.
Therefore there is no MOTEA MOTEB signals on Atari
please refer to http://pinouts.ru/Storage/InternalDisk_pinout.shtml
for more information

[DrCoolZic]

Question for Jeff
Just lazy looking at documentation
I have Hxc Floopy Emulator Rev C (USB type).
Is it possible to select by software
- enable / disable HxC (i.e. if disabled HxC has its output always TS)
- select if HxC respond to D0 or D1

(Just to compare with CosmosEx see below)

[DrCoolZic]

Hello I am reviving this thread because I am trying to connect a CosmosEx floppy emulator to Atari ST.
This is very similar to connecting HxC floppy emulator.

Here is the wanted configuration: I want to have the CosmosEx device inside the Atari as a replacement for the internal floppy drive as this allows also an easy connection to the KB injector.
With this configuration I would like to be able to still use an external real floppy drive.

Of course the solution described in this thread for the HxC (with switch to toggle drive A or B) can be used.
However as the CosmosEx device offers the capability (by software) to be disabled or when enabled to be seen as drive 0 or 1 there might be a simpler solution.

We first sets the internal straps so that DS0 and DS1 are routed to pin 5 and 6 of the DB14 connector.
Now if we need CosmosEx as drive A it must be enabled and set to 0 and we can connect at the same time the external drive as drive B using the DS1 select.
If we need to have the external floppy drive as drive A and CosmosEx as drive B then we enable the CosmosEx and set it to 1 and the external floppy drive just need to use the DS0 signal.

[DrCoolZic]

I have completed the mod and tested it with my HxC floppy emulator - I can now toggle the HxC to behave as DS0 for loading games or flick the switch back for normal 'legacy' floppy use.
...
We now need a good line on the board for DS0 and DS1. These can be found at W301 (DS0) and W300 (DS1) handily located near the sound chip. Flip the board over and remove the solder from pin 1 at each of these points using a vacuum pump:

This mod works perfect to inverse the DS0 1 DS1 line.
So internal drive DS0 1 DS1 line get inverted but on the DIN14 only pin 5 get inverted (DS0 or DS1) pin 6 stay stuck to logic 1 (deselected).
If you want also to provide switching of DS0 and DS1 between pin 5 and 6 you will have to cut the trace between W300 2-3 and place a wire between 1-2

[Jeff_HxC2001]

Question for Jeff
Just lazy looking at documentation
I have Hxc Floopy Emulator Rev C (USB type).
Is it possible to select by software
- enable / disable HxC (i.e. if disabled HxC has its output always TS)

Yes sure !

- select if HxC respond to D0 or D1

Sure again.

(see app picture)

Image1.png

[DrCoolZic]

Thanks for the information. I must admit that I have not used my HxC for quite some times

[troed]

I've now begun actually modifying my STE and am about to make the A<->B switch. I'll go for the non-leg cutting/bending method on the wiki since my sound chip isn't socketed.

Now done. The described no-pin-cutting method doesn't swap the signals on the internal cable so I had to make a few modifications to it: http://blog.troed.se/2014/10/21/atari-s ... nd-b-swap/

/Troed

[metalages]

HXC in external drive box + drive selector.
Excellent idea

[qq1975b]

To be honest I don't understand that diagram. What do I need to make this work.

You need one double toggle switch (according to Wikipedia it is called a DPDT http://en.wikipedia.org/wiki/Switch and it normally looks something like this):

You have to cut pin 19 and 20 of the sound chip and solder a wire to it. Each wire goes to two contacts on the switch. One middle contact of the switch is connected to drive A select, the other to drive B select:
floppy switch.png
That is all.

Warning: doing it wrong may well kill your sound chip.

Hans Wessels

Can any DPDT switch be used? I mean there are on-off-on, on-on, 120V, 250V....

Like this one? http://es.farnell.com/multicomp/1md3t1b ... dp/9473530

thank you.

[Dal]

You need the on-on type really. on-off-on will work, but the middle position will be useless as neither drive would be selected.

[mpattonm]

Just in case anyoe is interested, this is how I installed A-B drive switch on STE:

[mpattonm]

..part 2 of pics

[poiex]

Just in case anyoe is interested, this is how I installed A-B drive switch on STE:

Did you cut any tracks on the mobo or bent any sound chip legs?
I'm gonna do the same installation with my STE, just wasn't sure those black wires with connectors on them.
And where to cut tracks with STE if its needed?

[mpattonm]

I have chosen "track cut" method. Instructions are on the first page of this thread.

[tzok]

I have not tested it, but there is a way without (well, almost) cutting and/or bending any pins. It has two variants (STe only).

* First variant is to install ID switch (1P2T) in the Atari, and in the external drive. ID0 for EPSON SMD380 is by shorting pins 14 & 15, while ID1 is by shorting pins 15 and 16. You have to enable DS0 signal for external floppy by cutting a bridge between pins 2 & 3 of W300 and connecting pin 2 of W300 with pin 1 of W301. The drawback is that you have to move 2 independent switches to swap drives A and B.

* Second variant requires only one switch in the Atari. It has to be a two circuit ON-ON switch (2P2T). One circuit switches the internal drive by shorting jumpers 14 or 16 with 15. Second circuit switches pin 2 of W301 between 1 (DS0) and 3 (DS1), effectively switching external drive between ID0 and ID1. In this case you have to cut bridge between pins 2 & 3 of W301.
Be careful and think what you're doing - it has to be a cross-switch:
- in one position internal drive is ID0 (SMD380 pins 14 & 15 shorted) and DS1 signal is routed to the external drive (W301 pins 2 & 3 shorted),
- in second switch position it should be opposite: internal FDD is ID1 (SMD380 pins 16 & 15 shorted), and DS0 (W301 pins 2 & 1 shorted) is routed to the external FDD.

Pin 1 of W30x is a square pad.

***

I have tested method 2 and it works without problems. No need for cutting tracks on ST mainboard.

[moebiusrising]

What if my internal floppy port is damaged, ie: broken traces, is there a way to permanently "hard wire" this for a 1040STF for external port only? What steps does one skip?

[Methanoid]

What 1024Mak and Dal have done is different (and confusing me).

Mak's seems less work and less dangerous... What is the advantage of Dal's then?

I tried to read http://www.atari-wiki.com/index.php/Dri ... t_Swap_Mod but in 3 browsers the page loads nothing (yet the Wiki index shows there is text to load!)

I have two STE's and will have external Goteks that I would use for most of the time to boot the STEs but sometimes I would like to boot from internal FDD (they both still work fine after all!)