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____________________________________________________ DS34T101, DS34T102, DS34T104, DS34T108
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Table 9-7. Ethernet PHY Interface Pins (MII/RMII/SSMII)
The PHY interface type is configured by
General_cfg_reg0.MII_mode_select[1:0]. 00=MII, 01=Reduced MII (RMII), 11=Source Synchronous
Serial MII (SSMII). The MII interface is described in IEEE 802.3-2005 Section 22. The RMII interface is described in this document:
PIN DESCRIPTION
CLK_MII_TX
I
MII Transmit Clock Input
In MII mode a 25MHz clock must be applied to this pin to clock the transmit side of
device on the rising edge of CLK_MII_TX. See the timing diagram in
Figure 14-22.
In RMII mode a 50MHz clock must be applied to this pin to clock the transmit side
of the interface.
MII_TXD[3:2] and
MII_TX_EN are clocked out of the device on the
rising edge of CLK_MII_TX. See the timing diagram in
Figure 14-24.
In SSMII mode, a 125MHz clock must be applied to this pin. This clock is the
CLK_SSMII_TX
O
12ma
SSMII Transmit Clock Output
In SSMII mode, the device provides a 125MHz clock on this pin to clock the
(SSMII_TX_SYNC) are clocked out of the device on the rising edge of
and RMII modes.
MII_TXD[3:0]
O
8mA
MII Transmit Data Outputs
In MII mode, transmit data is passed to the PHY four bits at a time on
MII_TXD[3:0] on the rising edge of
CLK_MII_TX. See the timing diagram in
Figure 14-22.
In RMII mode, transmit data is passed to the PHY two bits at a time on
MII_TXD[3:2] on the rising edge of
CLK_MII_TX while MII_TXD[1:0] are not used.
See the timing diagram in
Figure 14-24.
In SSMII mode, transmit data is passed to the PHY one bit at a time on MII_TXD[0]
(SSMII_TX_SYNC) indicates 10-bit segment alignment of the serial data stream.
MII_TX_EN
O
8mA
MII Transmit Enable Output
In MII mode and RMII, this pin serves as the transmit enable output. In SSMII
mode this pin is not used.
MII_TX_ERR
O
8mA
MI Transmit Error Output
In MII mode this pin serves as the transmit error output. In RMII and SSMII modes
this pin is not used.
CLK_MII_RX
I
MII Receive Clock Input
and
MII_RX_ERR are clocked into the device on the rising edge of CLK_MII_RX.
In RMII mode this pin is not used, and a 50MHz clock applied to
CLK_MII_TXprovides timing for both transmit and receive sides of the interface.
MII_RXD[3:2],
In SSMII mode a 125MHz clock from the PHY must be applied to this pin.
the device on the rising edge of CLK_MII_RX. See the timing diagram in