GT-64260A Design Guide
Doc. No. MV-S300165-00, Rev. A
CONFIDENTIAL
Copyright © 2002 Marvell
Page 136
Document Classification: Proprietary Information
May 21, 2002, Preliminary
document, the specifications documents takes precedence. This documents provides additional
information but does not replace the specification documents.
The RMII signals output delay is measured using the test circuit in
Simulating the GT-64260A RMII signals test circuit gives a reference point of 2.1 ns. (See
Table 30:
RMII AC timing for 50 MHz (from RMII Specification Rev. 1.2 Document)
Symbol
Parameter
Min
Typ
Min
Units
REF_CLK Frequency
50
MHz
REF_CLK Duty Cycle
35
65
%
Tsu
TXD[1:0], TX_EN, RXD[1:0], CRS_DV, RX_ER
Data setup to REF_CLK rising edge
4
ns
Thold
TXD[1:0], TX_EN, RXD[1:0], CRS_DV, RX_ER
Data hold from REF_CLK rising edge
2
ns
Table 31:
Ethernet RMII Interface
NOTE:
All receive pins Setup, and Hold times refer to the RxClk rising edge. All transmit pins Output Delays, Setup, and
Hold times refer to the TxClk rising edge.
The multiplier in the following timing numbers is 1 for 100Mb/s operation, and 10 for 10Mb/s operation
Signals
Descrip tion
133MHz
Units
Loading
RMII Clock
Frequency
50
Mhz
RMII Clock
Clock Period
20
ns
DvCRS, RxD[1:0]
Setup
2
ns
DvCRS, RxD[1:0]
Hold
1
ns
TxD[1:0],TxEN
Output Delay
3
10
ns
20pf