Freescale Semiconductor i.MX 6SoloLite Linux, Справочное руководство

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In MII mode, there are 18 signals defined by the IEEE 802.3 standard and supported by
the EMAC. MII, RMII modes uses a subset of the 18 signals. These signals are listed in
table below.
Table 27-1. Pin Usage in MII, RMII
Direction EMAC Pin
Name
MII Usage RMII Usage RGMII Usage (i.MX 6SL cannot
support)
In/Out FEC_MDIO Management Data Input/Output Management Data
Input/output
Management Data Input/Output
Out FEC_MDC Management Data Clock General output Management Data Clock
Out FEC_TXD[0] Data out, bit 0 Data out, bit 0 Data out, bit 0
Out FEC_TXD[1] Data out, bit 1 Data out, bit 1 Data out, bit 1
Out FEC_TXD[2] Data out, bit 2 Not Used Data out, bit 2
Out FEC_TXD[3] Data out, bit 3 Not Used Data out, bit 3
Out FEC_TX_EN Transmit Enable Transmit Enable Transmit Enable
Out FEC_TX_ER Transmit Error Not Used Not Used
In FEC_CRS Carrier Sense Not Used Not Used
In FEC_COL Collision Not Used Not Used
In FEC_TX_CLK Transmit Clock Not Used Synchronous clock reference (REF_CLK,
can connect from PHY)
In FEC_RX_ER Receive Error Receive Error Not Used
In FEC_RX_CLK Receive Clock Not Used Synchronous clock reference (REF_CLK,
can connect from PHY)
In FEC_RX_DV Receive Data Valid Receive Data Valid
and generate CRS RXDV XOR RXERR on the falling edge
of FEC_RX_CLK.
In FEC_RXD[0] Data in, bit 0 Data in, bit 0 Data in, bit 0
In FEC_RXD[1] Data in, bit 1 Data in, bit 1 Data in, bit 1
In FEC_RXD[2] Data in, bit 2 Not Used Data in, bit 2
In FEC_RXD[3] Data in, bit 3 Not Used Data in, bit 3
The MII management interface consists of two pins, FEC_MDIO, and FEC_MDC. The
FEC hardware operation can be divided in the parts listed below. For detailed information
consult the i.MX 6SoloLite Multimedia Applications Processor Reference Manual.
• Transmission-The Ethernet transmitter is designed to work with almost no
intervention from software. Once ECR[ETHER_EN] is asserted and data appears in
the transmit FIFO, the Ethernet MAC is able to transmit onto the network. When the
transmit FIFO fills to the watermark (defined by the TFWR), the MAC transmit logic
asserts FEC_TX_EN and starts transmitting the preamble (PA) sequence, the start
frame delimiter (SFD), and then the frame information from the FIFO. However, the
controller defers the transmission if the network is busy (FEC_CRS asserts).
Hardware Operation
i.MX 6SoloLite Linux Reference Manual, Rev. L3.0.35_4.1.0, 09/2013
174 Freescale Semiconductor, Inc.