Re: [hatari-devel] Re: Hatari floppy drive detection with EmuTOS

["Roger Burrows" <rfburrows@xxxxxxxxx>]

On 16 Jan 2014 at 18:50, Nicolas Pomarède wrote:
> Le 16/01/2014 18:28, Roger Burrows a écrit :
> > On 16 Jan 2014 at 10:46, Nicolas Pomarède wrote:
> >>
> >> Do you have the possibility to test this on a real ST :
> >>    - connect drive A and disconnect drive B as above
> >>    - but in the drive detection test, test drive B first, then drive A.
> >>
> >> I'd like to know the delay you get in that case where spinup is made
> >> first on the disconnected drive.
> >>
OK, the following runs were made with floppy 1 tested first, then floppy 0..

1. Drive 0 connected, drive 1 disconnected:
  Drive 1: timeout (3 seconds)
  Drive 0: 255 ticks
2. Both drives connected
  Drive 1: 361 ticks
  Drive 0: 26 ticks

For some reason, the timeout is working as expected here ...

On a related topic, I looked at your disassembly of TOS code.  It seems that
TOS delays for approximately 60 microseconds before and after accessing the
command/status register (I'm assuming a clock speed of 8MHz).  I have two
questions:
1. What is the minimum delay necessary?
2. Is this delay the same for any FDC register access (e.g. track register)?

I ask because EmuTOS currently delays just 3 microseconds.

Roger