exxos's Atari, Amiga & retro forum

If internal and external were DS0 by design, why would Atari put DRIVE0 and DRIVE1 select on separate lines to the external floppy connector ?

EDIT:

Actually looking at the STFM schematic, DRIVE1 and DRIVE0 and actually wired together on the floppy connector, both wired to DRIVE1. Internal is wired to DRIVE0.

exxos wrote: 08 Jan 2019 12:01 If internal and external were DS0 by design, why would Atari put DRIVE0 and DRIVE1 select on separate lines to the external floppy connector ?

This is only for models without internal drive so that you could connect two external drives.

Actually looking at the STFM schematic, DRIVE1 and DRIVE0 and actually wired together on the floppy connector, both wired to DRIVE1. Internal is wired to DRIVE0.

Right. In models with internal drive external DS0 is connected (by default) to drive 1.

And Atari external drives have the same swap for the drive out connector, so that if you daisy chain a second drive, again, it should be configured as DSO. This obviously is only useful for models without internal drives.

exxos wrote: 08 Jan 2019 11:49 I had to check my MPF image to check, Internal on the ST is DS0. So external should be DS1.

I don't know of the external drive you are using. But maybe its just wired up as a different drive select line by default ? I would check the ST floppy connector end, DS1 and DS0 are on there.. I'm assuming if you swap them in the connector, then it should all work how it should then.

I will see if I can get time to buzz it out and see if there is a cable select 'twist' like in the original cable:
Because I'm lucky enoughto have a couple of floppies that do have jumpers for DS0 and they only work in this enclosure when set to DS0, which suggests cable select is at play as per the picture, though within the external drive cable.

ijor wrote: 08 Jan 2019 11:54 The ST is designed so that all drives, internal and external, should be configured as DS0. Due to the internal wiring, an external drive configured as DS0 will be seen as DS1 by the computer.

If the drive can't be configured as DS0 (Gotek certainly can), then you need to switch the signals somehow by yourself.

Note that there are two completely different types of cable twisting. One is that for a non Atari drive mechanism, including Gotek of course, the whole cable must be twisted. The IDE connector is reversed. This is unrelated to twisting the drive select/motor signals to swap DS0 with DS1.

Cool, I thought tah might be the case, but going mad looking at it!

By cable twist, I don't mean cable inversion like with the Gotek, but rather the cable select twist that switches the drive A/B select and motor enable signals on an old fashioned floppy cable, between connectors.

rubber_jonnie wrote: 08 Jan 2019 12:39 By cable twist, I don't mean cable inversion like with the Gotek, but rather the cable select twist that switches the drive A/B select and motor enable signals on an old fashioned floppy cable, between connectors.

I'm not sure that would work because the ST uses a single motor on signal. And note that depending on the case, you might need both twists. That is, if you connect a third party drive configured as DS1 to an enclosure designed for Atari drives (or as an internal drive), then you have both to invert the cable and to swap the select signals.

ijor wrote: 08 Jan 2019 13:23

rubber_jonnie wrote: 08 Jan 2019 12:39 By cable twist, I don't mean cable inversion like with the Gotek, but rather the cable select twist that switches the drive A/B select and motor enable signals on an old fashioned floppy cable, between connectors.

I'm not sure that would work because the ST uses a single motor on signal. And note that depending on the case, you might need both twists. That is, if you connect a third party drive configured as DS1 to an enclosure designed for Atari drives (or as an internal drive), then you have both to invert the cable and to swap the select signals.

The enclosure I have (Datel RF302R) only works with a drive set to DS0, I have tested it with a 1040STF, and it works fine in this configuration, with copying between A: and B:, formatting etc all working fine. Switching the external drive to be DS1 does not work, which is why I believe cable select is at play. I don't have to invert the cables at all.

I can't see how it would work without cable select if both drives are set to DS0.

rubber_jonnie wrote: 08 Jan 2019 13:40 The enclosure I have (Datel RF302R) only works with a drive set to DS0, I have tested it with a 1040STF, and it works fine in this configuration, with copying between A: and B:, formatting etc all working fine. Switching the external drive to be DS1 does not work, which is why I believe cable select is at play. I don't have to invert the cables at all.

I can't see how it would work without cable select if both drives are set to DS0.

I didn't say you should not swap the select signals. I said you should better not swap the motor on signals as a twisted PC cable normally does. It might still work or not depending on the drive. See this for an explanation of the issue and how it still might work, and an elaboration of the two different floppy 34-pin standards:
http://www.atari-forum.com/viewtopic.php?f=99&t=26656

ijor wrote: 08 Jan 2019 13:55

rubber_jonnie wrote: 08 Jan 2019 13:40 The enclosure I have (Datel RF302R) only works with a drive set to DS0, I have tested it with a 1040STF, and it works fine in this configuration, with copying between A: and B:, formatting etc all working fine. Switching the external drive to be DS1 does not work, which is why I believe cable select is at play. I don't have to invert the cables at all.

I can't see how it would work without cable select if both drives are set to DS0.

I didn't say you should not swap the select signals. I said you should better not swap the motor on signals as a twisted PC cable normally does. It might still work or not depending on the drive. See this for an explanation of the issue and how it still might work, and an elaboration of the two different floppy 34-pin standards:
http://www.atari-forum.com/viewtopic.php?f=99&t=26656

Ahh, very interesting, I shall have a read of that, the cable looks awfully similar to mine.

Small update. I now have the enclosure properly working with a replacement floppy drive.

The drive is set to DS0 by jumper. I also tested with a Gotek also set to DS0 in place of the floppy and it also worked ok, and I was able to copy files etc between the Gotek at drive B: and the internal floppy at drive A:

So the original floppy seems to have been the problem, so stage one fix is done, I know it actually works. PSU is 12v/1A with centre positive if anybody else needs to know.

Next step is to read the detail of what was kindly sent over by ijor, as I'd like to make up another drive from the spares I have to use with my 520ST, since whilst it boots fine with an empty drive, it gives a 2 bomb crash when trying to access the floppy drive.

Will see where I get to and update, but I have a sat nav to fit to my car first! Stupid priorities!

So DS0 is now set for internal and external drives ?

I'm sure my external drives are all set do DS1. I mean I used to make external drives with MPF's years ago and sure I had to swap them to DS1. Unless DRIVE1 is actually wired to DS0 on the drive, then that would make sense.