4 mii interface, 1 mii interface signals, Mii interface – BECKHOFF ET1200 User Manual
Page 34: Mii interface signals, Figure 3: mii interface signals
MII Interface
III-24
Slave Controller
– ET1200 Hardware Description
4
MII Interface
The ET1200 is connected with Ethernet PHYs using the MII interface. The MII interface of the ET1200
is optimized for low processing/forwarding delays by omitting a transmit FIFO. To allow this, the
ET1200 has additional requirements to Ethernet PHYs, which are easily accomplished by several PHY
vendors.
Refer to “Section I – Technology” for Ethernet PHY requirements.
Additional information regarding the ET1200:
The clock source of the PHYs is either CLK25OUT of the ET1200, or the clock signal that is
connected to OSC_IN if a quartz oscillator is used.
The signal polarity of LINK_MII is not configurable, LINK_MII has to be active low.
The TX_CLK signal of the PHYs is not connected to the ET1200. The ET1200 does not use the
MII interface for link detection or link configuration.
For details about the ESC MII Interface refer to Section I.
4.1
MII Interface Signals
The MII interface of the ET1200 has the following signals:
EtherCAT
device
RX_CLK
LINK_MII
RX_DV
RX_ERR
RX_D[3:0]
TX_ENA
MI_CLK
TX_D[3:0]
MI_DATA
PHYAD_OFF
Figure 3: MII Interface signals