30 Oct
2010
30 Oct
'10
12:58 p.m.
On 30/10/10 20:29, Dave McGuire wrote:
You could stick a little AD9833 (or similar) DDS chip
on there. It's
overkill, but they're pretty cheap now, and you'll get the desired
frequency spot-on.
?8.25 each with no quantity discount is *not* cheap. The FPGA only costs
a few quid more than that.
Digikey have them for ?5.86, but that's still more than a crystal. I
wonder how the host adapters for the SA1000s generated this clock
frequency... it does seem somewhat odd.
The other thing is, I'd be concerned about releasing hardware with
SA1000 support without testing it on an actual drive. I'm willing to bet
the chances of me finding a working SA1000 in 230V/50Hz configuration
are somewhere between 'slim' and 'nil'.
I'll guarantee ST506 support though, given that I've got an ST277R RLL
drive and controller here. Just need an MFM controller for it, or the
RLL code tables for the Seagate ST21R or ST22R controller (which IIRC
uses an Adaptec AIC010 chip)...
--
Phil.
classiccmp at philpem.me.uk
http://www.philpem.me.uk/