MCIMX35 Motorola Semiconductor Products, MCIMX35 Datasheet - Page 54

• Manufacturer Part Number: MCIMX35
• Manufacturer: Motorola Semiconductor Products

4.7.8
This section describes the electrical information of the FEC module. The FEC is designed to support both
10- and 100-Mbps Ethernet networks. An external transceiver interface and transceiver function are
required to complete the interface to the media. The FEC supports the 10/100 Mbps Media Independent
Interface (MII) using a total of 18 pins. The 10-Mbps 7-wire interface that is restricted to a 10-Mbps data
rate uses seven of the MII pins for connection to an external Ethernet transceiver.
4.7.8.1
This section describes the AC timing specifications of the FEC. The MII signals are compatible with
transceivers operating at a voltage of 3.3 V.
4.7.8.2
The MII receive timing signals consist of FEC_RXD[3:0], FEC_RX_DV, FEC_RX_ER, and
FEC_RX_CLK. The receiver functions correctly up to a FEC_RX_CLK maximum frequency of
25 MHz + 1%. There is no minimum frequency requirement. Additionally, the processor clock frequency
must exceed twice the FEC_RX_CLK frequency.
1
Figure 28
54
FEC_RX_DV, FEC_RX_CLK, and FEC_RXD0 have the same timing when in 10 Mbps 7-wire interface mode.
Num
M1
M2
M3
M4
MCIMX35 (i.MX35) Multimedia Applications Processor for Automotive Products Advance Information, Rev. 0
FEC_RXD[3:0], FEC_RX_DV, FEC_RX_ER to FEC_RX_CLK setup
FEC_RX_CLK to FEC_RXD[3:0], FEC_RX_DV, FEC_RX_ER hold
FEC_RX_CLK pulse width high
FEC_RX_CLK pulse width low
FEC_RXD[3:0] (inputs)
FEC_RX_CLK (input)
shows the MII receive signal timings listed in
Fast Ethernet Controller (FEC) AC Electrical Specifications
FEC AC Timing
MII Receive Signal Timing
FEC_RX_ER
FEC_RX_DV
Figure 28. MII Receive Signal Timing Diagram
Characteristic
Preliminary—Subject to Change Without Notice
Table 40. MII Receive Signal Timing
M1
1
M2
Table 40
M3
Table
lists MII receive channel timings.
40.
Min.
35%
35%
5
5
M4
Max.
65%
65%
—
—
Freescale Semiconductor
FEC_RX_CLK period
FEC_RX_CLK period
Unit
ns
ns