SMSC LAN8720i User Manual
Small Footprint RMII 10/100 Ethernet Transceiver with HP Auto-MDIX Support
Datasheet
SMSC LAN8720/LAN8720i
55
Revision 1.0 (05-28-09)
DATASHEET
Chapter 6 AC Electrical Characteristics
The timing diagrams and limits in this section define the requirements placed on the external signals
of the Phy.
of the Phy.
6.1
Serial Management Interface (SMI) Timing
The Serial Management Interface is used for status and control as described in
.
Figure 6.1 SMI Timing Diagram
Table 6.1 SMI Timing Values
PARAMETER
DESCRIPTION
MIN
TYP
MAX
UNITS
NOTES
T1.1
MDC minimum cycle time
400
ns
T1.2
MDC to MDIO (Read from PHY)
delay
delay
0
30
ns
T1.3
MDIO (Write to PHY) to MDC setup
10
ns
T1.4
MDIO (Write to PHY) to MDC hold
10
ns
Clock -
MDC
Data Out -
MDIO
T
1.2
Valid Data
(Read from PHY)
T
1.1
T
1.3
T
1.4
Data In -
MDIO
Valid Data
(Write to PHY)