mcimx27- Freescale Semiconductor, Inc, mcimx27- Datasheet - Page 59

• Manufacturer Part Number: mcimx27-
• Description: Multimedia Applications Processor
• Manufacturer: Freescale Semiconductor, Inc

1
3.6.2.4
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
Freescale Semiconductor
M10
M11
M12
M13
M14
M15
M9
ID
FEC_COL has the same timing in 10 Mbit 7-wire interface mode.
1
ID
FEC_MDC falling edge to FEC_MDIO output invalid (minimum propagation delay)
FEC_MDC falling edge to FEC_MDIO output valid (max propagation delay)
FEC_MDIO (input) to FEC_MDC rising edge setup
FEC_MDIO (input) to FEC_MDC rising edge hold
FEC_MDC pulse width high
FEC_MDC pulse width low
FEC_MDIO (output)
FEC_MDC (output)
FEC_MDIO (input)
shows the MII serial management channel timings, and
FEC_CRS to FEC_COL minimum pulse width
MII Serial Management Channel Timing (FEC_MDIO and FEC_MDC)
Table 28. MII Serial Management Channel Timing Parameters
Table 27. MII Asynchronous Inputs Signal Timing Parameter
Figure 20. MII Serial Management Channel Timing Diagram
Parameter
Preliminary—Subject to Change Without Notice
i.MX27 and i.MX27L Data Sheet, Rev. 1.2
M12
Parameter
M13
M14
M10
M11
Table 28
Min
1.5
M15
lists the timing parameters.
Max
—
40% 60% FEC_MDC period
40% 60% FEC_MDC period
Min Max
—
18
0
0
FEC_TX_CLK period
—
—
—
5
Signal Descriptions
Unit
Unit
ns
ns
ns
ns
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