FreeLists / si-list / [SI-LIST] Re: setup & hold Time for source synchronous

["Lai, Ricky (Eng Hou)" <Ricky.Lai@xxxxxxxxxx>]

The correct equation should be:
Setup margin = Budget - (T_data_valid_before_stb_min) - (Tflight_skew_max) -
Tsetup
Hold margin  = Budget - (T_data_valid_after_stb_min) - (Tflight_skew_max) -
Thold

-----Original Message-----
From: Issa, Elie 
Sent: Friday, August 03, 2001 11:26 AM
To: 'si-list@xxxxxxxxxxxxx'
Subject: [SI-LIST] setup & hold Time for source synchronous



Dear SI Gurus:
I need  your help in verifying some derivation for setup & hold equations
for GTL bus
for source synchronous clocks.

The equation for setup is:
Tco(strobe)min + Tflight(strobe)min - Tco(data)max -Tflight(data)max
-Tsetup= Tmargin_setup

The equation for hold time was:
Tco(data)min    + Tflight(data)min  -Tco(strobe)max -Tflight(strobe)max
-Thold= Tmargin_hold

The skew for the strobe & data  flight time should be very small.  Whenever,
I fit the variable given in the
specs into the equation, the margin comes negative.

I would think that there must be a ValidBefore and ValidAfter variable to be
included in the equation. 
Yet the specs claim the ValidBefore is only [Tco(strobe)min-- Tco(data)max].


Any input would be greatly appreciated!

Regards
Elie



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