|Re: [hatari-devel] fdc test for real hardware|
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On 22/09/2013 23:11, Roger Burrows wrote:
On 22 Sep 2013 at 22:55, Nicolas Pomarède wrote:
On 22/09/2013 21:49, Roger Burrows wrote:
On 22 Sep 2013 at 19:32, Nicolas Pomarède wrote:
Could someone with a working STF/STE test this program and post the
results ? I need results from different machine to measure the relation
between RPM and index duration.
On my 1040STF:
Thanks for your results ; are these pal or ntsc model ?
These are with an NTSC model.
After converting those numbers to RPM (taking cpu clock into account), I
get very stable RPM for STF, but STE's ones are sometimes changing
significantly for no apparent reason :
my 520 STF PAL : 299.6 - 299.7 RPM
roger's 1040 STF NTSC : 300.3 RPM
roger's 1040 STE NTSC : 300.78 RPM but sometimes 299.19 RPM
ragnar76's 1040 STE PAL : 300.86 RPM but sometimes 299.26 RPM
For STF, index time is stable, 1.88% or 1.94 % of total revolution's time
But for STE, identical RPM sometimes give different index time (for
example 300.78 RPM, but 1.35%, 1.22%, 1.09%), which is quite odd. Maybe
there's something different in the STE wiring for the FDC, but that was
not my impression when looking at the board's schematic. Or maybe it's
just because drive and/or floppy are old.
Having different RPM between machine is not a problem, it depends on the
drive's initial seting ; but once the motor is spinning, RPM should be
fairly stable, which is not the case for those STE.
Anyway, I don't know any program that rely on such high precision for
the duration of the index signal. I will use the STF's ones as they're