MCIMX27 Motorola Semiconductor Products, MCIMX27 Datasheet - Page 58

• Manufacturer Part Number: MCIMX27
• Manufacturer: Motorola Semiconductor Products

1
Signal Descriptions
3.5.8.3
Figure 19
1
3.5.8.4
The FEC functions correctly with a maximum MDC frequency of 2.5 MHz. The MDC frequency should
be equal to or less than 2.5 MHz to be compliant with IEEE 802.3 MII specification. However the FEC
can function correctly with a maximum MDC frequency of 15 MHz.
Figure 20
58
M5
M6
M7
M8
M9
FEC_TX_EN, FEC_TX_CLK, and FEC_TXD0 have the same timing in 10 Mbps 7-wire interface mode.
FEC_COL has the same timing in 10 Mbit 7-wire interface mode.
1
ID
ID
FEC_TXD[3:0] (outputs)
FEC_TX_CLK (input)
FEC_TX_CLK to FEC_TXD[3:0], FEC_TX_EN, FEC_TX_ER invalid
FEC_TX_CLK to FEC_TXD[3:0], FEC_TX_EN, FEC_TX_ER valid
FEC_TX_CLK pulse width high
FEC_TX_CLK pulse width low
shows the MII asynchronous input timings, and
shows the MII serial management channel timings, and
FEC_CRS to FEC_COL minimum pulse width
FEC_CRS, FEC_COL
MII Asynchronous Inputs Signal Timing (FEC_CRS and FEC_COL)
MII Serial Management Channel Timing (FEC_MDIO and FEC_MDC)
FEC_TX_EN
FEC_TX_ER
Table 26. MII Asynchronous Inputs Signal Timing Parameter
Figure 19. MII Asynchronous Inputs Signal Timing Diagram
Table 25. MII Transmit Signal Timing Parameters
Figure 18. MII Transmit Signal Timing Diagram
i.MX27 Data Sheet, Advance Information, Rev. 0.1
Parameter
Preliminary—Subject to Change Without Notice
Parameter
1
M5
M6
M7
Table 26
M9
Table 27
Min
1.5
lists the timing parameters.
M8
35%
35%
Min
—
5
lists the timing parameters.
Max
—
65%
65%
Max
20
—
Freescale Semiconductor
FEC_TX_CLK period
FEC_TX_CLK period
FEC_TX_CLK period
Unit
Unit
ns
ns