Ultra 160/m clocking question
r_moore at qlc.com
Thu Feb 11 11:00:56 PST 1999
* From the T10 Reflector (t10 at symbios.com), posted by:
* Richard Moore <r_moore at qlc.com>
The answer (for SPI-3 rev 2) is given in Table 32. This table applies to DT
is for ST) and shows the Fast-20 REQ/ACK period (from one assertion edge to
to be 100 ns, so the REQ frequency is 10 MHz. With DT this means 20
hence it is called Fast-20.
The "XX" in Fast-XX gives the maximum transfer rate, in Megatransfers/s,
that can be
supported using that particular set of timing parameters. This transfer rate
is equal to
the REQ/ACK frequency for ST or twice the REQ/ACK frequency for DT.
-- Richard Moore
> -----Original Message-----
> From: Ken Erickson [mailto:Ken.Erickson at quantum.com]
> Sent: Thursday, February 11, 1999 10:34 AM
> To: 't10 at symbios.com'
> Subject: Ultra 160/m clocking question
> * From the T10 Reflector (t10 at symbios.com), posted by:
> * Ken Erickson <Ken.Erickson at quantum.com>
> I have a question regarding single edge / double edge
> clocking and FAST
> clocking options. If the host issues the PPR message with DT
> and FAST-20
> clocking is the REQ rate 10Mhz or 20Mhz? In other words, is ST/DT
> independent of the transfer period factor?
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