HxC + original floppy both connected - how to disable motor?

General discussion forum - for all that doesn't fit in any other category.
Post Reply
troed
Posts: 9
Joined: Fri May 18, 2012 5:38 pm

HxC + original floppy both connected - how to disable motor?

Post by troed »

(This specific setup is on the Atari ST, but the information should be "Shugart" general I believe)

I have an HxC SD floppy emu connected at the same time as the original floppy drive in an Atari ST. Everything works fine, but since there's a single MOTOR ON signal the internal drive spins whenever I use the HxC. 99.99% of the time I use the computer, I'm only interested in using the HxC. The original floppy is there for the external looks, as well as for the few times I preserve original disks.

What do I need to do to only have the motor of the internal drive running when it's _actually_ accessed? I've googled for logic traces on the Drive Select signals for a while but unfortunately I'm still not sure. If this trace is correct - is using the internal Drive Select in place of Motor On Really Bad(tm)? Should I build an AND gate instead?

http://www.ianstedman.co.uk/downloads/x ... t_zoom.png

regards,
Troed - software, not electrical, engineer

Jeff
Site Admin
Posts: 8092
Joined: Fri Oct 20, 2006 12:12 am
Location: Paris
Contact:

Re: HxC + original floppy both connected - how to disable mo

Post by Jeff »

i think that the best to do this is just to add a switch between the ST and the floppy drive on the MOTOR ON line to disable it when needed.
This line cannot be easily gated without possible issue, so the switch is the better option.

troed
Posts: 9
Joined: Fri May 18, 2012 5:38 pm

Re: HxC + original floppy both connected - how to disable mo

Post by troed »

Jeff wrote:i think that the best to do this is just to add a switch between the ST and the floppy drive on the MOTOR ON line to disable it when needed.
This line cannot be easily gated without possible issue, so the switch is the better option.
Thanks Jeff - I trust your expert knowledge on this. I assume the issue is that I cannot trust drive select to be low at all times motor on needs to be? (or too little time to spin up)

/Troed

Post Reply