SPRUI30H November 2015 – May 2024 DRA745 , DRA746 , DRA750 , DRA756
Figure 24-188 shows a device with integrated GMAC_SW and MDIO interfaced via a RMII connection in a typical system. The individual CPSW and MDIO signals for the RMII interface are summarized in Table 24-868.
For more information, refer to either the IEEE 802.3 standard or ISO/IEC 8802-3:2000(E).
Signal | Device Pin(s) | I/O(1) | Description |
---|---|---|---|
TXD[1:0] | rmii0_txd[1:0] rmii1_txd[1:0] | O | Transmit data . The transmit data pins are a collection of 2 bits of data. TXD0 is the least-significant bit (LSB). The signals are synchronized by RMII_MHZ_50_CLK and valid only when TXEN is asserted. |
TXEN | rmii0_txen rmii1_txen | O | Transmit enable. The transmit enable signal indicates that the RMII_TXD pins are generating data for use by the PHY. RMII_TXEN is synchronous to RMII_MHZ_50_CLK |
RMII0_MHZ_50_CLK | RMII_MHZ_50_CLK | I/O | RMII reference clock. |
RMII1_MHZ_50_CLK | The reference clock is used to synchronize all RMII signals. RMII_MHZ_50_CLK must be continuous and fixed at 50 MHz. | ||
RXD[1:0] | rmii0_rxd[1:0] rmii1_rxd[1:0] | I | Receive data. The receive data pins are a collection of 2 bits of data. RXD0 is the least-significant bit (LSB). The signals are synchronized by RMII_MHZ_50_CLK and valid only when CRS_DV is asserted and RXER is de-asserted. |
CRS_DV | rmii0_crs rmii1_crs | I | Carrier sense/receive data valid. Multiplexed signal between carrier sense and receive data valid. |
RXER | rmii0_rxer rmii1_rxer | I | Receive error. The receive error signal is asserted to indicate that an error was detected in the received frame. |
MDIO_MDCLK | mdio_mclk | O | Management data clock (MDIO_MCLK). 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. |