Ethernet Interface Design Considerations
Timing Requirements
Copyright © 2002 Marvell
CONFIDENTIAL
Doc. No. MV-S300165-00, Rev. A
May 21, 2002, Preliminary
Document Classification: Proprietary Information
Page 137
Figure 82: GT-64260A RMII Signals Reference Point
GT-64260A to RMII PHY timing calculations:
Tcycle > Toutput_delay(GT-64260A) + Tsetup(PHY) + Tdelay(fly_time) + Tclock_skew
20 > 10 + 4 + Tdelay(fly_time) + 0.5
Tdelay(fly_time) < 5.5 ns
The fly time is measured from the GT-64260A reference point in
(2.1 ns) to the Vil measured on the
SDRAM pin (3.3 ns) in the figure below (board simulation).