SPRUI30H November 2015 – May 2024 DRA745 , DRA746 , DRA750 , DRA756
G/MII Interface can operate only in MII Mode.
The pin connections of the G/MII Interface is shown in Figure 24-187. The detailed description of the signals are listed in the following tables.
Signal | Device Pin(s) | I/O(1) | Description |
---|---|---|---|
MT_CLK | mii0_txclk mii1_txclk | I | The transmit clock is a continuous clock that provides the timing reference for transmit operations. The MTXD and MTXEN signals are tied to this clock. The clock is generated by the PHY and is 2.5 MHz at 10 Mbps operation and 25 MHz at 100 Mbps operation. |
MTXD[3:0] | mii0_txd[3:0] mii1_txd[3:0] | O | The transmit data pins are a collection of 4 data signals MTXD[3:0] comprising 4 bits of data. MTXD0 is the least-significant bit (LSB). The signals are synchronized by MT_CLK and valid only when MTXEN is asserted. |
MTXEN | mii0_txen mii1_txen | O | The transmit enable signal indicates that the MTXD pins are generating 4bit data for use by the PHY. It is driven synchronously by MT_CLK. |
MTXER | mii0_txer mii1_txer | O | Transmit data error. Used only for EEE to request PHY for low power transition. |
MCOL | mii0_col mii1_col | I | In half-duplex operation, the MCOL pin is asserted by the PHY when it detects a collision on the network. It remains asserted while the collision condition persists. This signal is not necessarily synchronous to MT_CLK nor MR_CLK. In full-duplex operation, the MCOL pin is used for hardware transmit flow control. Asserting the MCOL pin will stop packet transmissions; packets in the process of being transmitted when MCOL is asserted will complete transmission. The MCOL pin should be held low if hardware transmit flow control is not used. |
MCRS | mii0_crs mii1_crs | I | In half-duplex operation, the MCRS pin is asserted by the PHY when the network is not idle in either transmit or receive. The pin is de-asserted when both transmit and receive are idle. This signal is not necessarily synchronous to MT_CLK nor MR_CLK. In full-duplex operation, the MCRS pin should be held low. |
MR_CLK | mii0_rxclk mii1_rxclk | I | The receive clock is a continuous clock that provides the timing reference for receive operations. The MRXD, MRXDV, and MRXER signals are tied to this clock. The clock is generated by the PHY and is 2.5 MHz at 10 Mbps operation and 25 MHz at 100 Mbps operation. |
MRXD | mii0_rxd[0:3] mii1_rxd[0:3] | I | The receive data pins are a collection of 4 data signals comprising 4 bits of data. MRXD0 is the least-significant bit (LSB).The signals are synchronized by MR_CLK and valid only when MRXDV is asserted. |
MRXDV | mii0_rxdv mii1_rxdv | I | The receive data valid signal indicates that the MRXD pins are generating nibble data for use by the GMAC_SW. It is driven synchronously to MR_CLK. |
MRXER | mii0_rxer mii1_rxer | I | Receive Data Error input |
MDIO_MDCLK | mdio_mclk | O | Management data clock. The MDIO data clock is sourced by the MDIO module on the system. It is used to synchronize MDIO data access operations done on the MDIO_D pin. |
MDIO_D | mdio_d | I/O | MDIO data pin drives PHY management data into and out of the PHY by way of an access frame consisting of start of frame, read/write indication, PHY address, register address, and data bit cycles. The MDIO_D pin acts as an output for all but the data bit cycles at which time it is an input for read operations. |