SATA - is reduced rate signalling possible?

[RM]

Is it possible to operate a SATA drive at reduced signaling rate (i.e., less
than the nominal 1.5Mb/s)? It appears not all implementations recover the
embedded clock for sync - some may use a local clock (presumably at
1.5Mb/s), and use the embedded clock to resync. Yet there's just enough
weasel wording in the actual spec to make me believe that there was an
intention to allow reduced rate signaling.

Does anyone have any experience with this?

Thanks,
RM

 

[Peter]

Is it possible to operate a SATA drive at reduced signaling rate (i.e., less
than the nominal 1.5Mb/s)? It appears not all implementations recover the
embedded clock for sync - some may use a local clock (presumably at
1.5Mb/s), and use the embedded clock to resync. Yet there's just enough
weasel wording in the actual spec to make me believe that there was an
intention to allow reduced rate signaling.

Does anyone have any experience with this?

Thanks,
RM

Which wording makes you believe that?

All SATA-1 devices work at 1.5Gbit/sec serial stream rate.

 

[Arno Wagner]

Is it possible to operate a SATA drive at reduced signaling rate (i.e., less
than the nominal 1.5Mb/s)? It appears not all implementations recover the
embedded clock for sync - some may use a local clock (presumably at
1.5Mb/s), and use the embedded clock to resync. Yet there's just enough
weasel wording in the actual spec to make me believe that there was an
intention to allow reduced rate signaling.

Does anyone have any experience with this?

Since layer1 is syncronous, reduced rates would probably
need changed hardware, i.e. be impossible with existing
devices.

Arno

 

[RM]

Which wording makes you believe that?

Actually, the more I re-read, the clearer it is that 1.5Gb/s is basic to
Gen1 signalling. I guess it was just wishfull thinking. That high a rate is
going dictate an external PHY. So much for being creative.

All SATA-1 devices work at 1.5Gbit/sec serial stream rate.

Of course, I meant 1.5Gb/s. Thanks for the response.