Visible to Intel only — GUID: sfo1410068920341
Ixiasoft
Visible to Intel only — GUID: sfo1410068920341
Ixiasoft
18.3.2. FPGA EMAC I/O Signals
Signal Name |
In/Out |
Width |
Description |
|
---|---|---|---|---|
emac_clk_tx_i | Transmit Clock |
In |
1 |
This is the transmit clock (2.5 MHz/25 MHz) provided by the MII PHYs only. This clock comes from the FPGA Interface and is used for TX data capture. This clock is not used in GMII mode.
Note: This clock must be able to perform glitch free switching between 2.5 and 25 MHz.
|
emac_phy_txclk_o | Transmit Clock Output |
Out |
1 |
In GMII mode, this signal is the transmit clock output to the PHY to sample data. For MII, this clock is unused. |
emac_phy_txd_o[7:0] | PHY Transmit Data |
Out |
8 |
These are a group of eight transmit data signals driven by the EMAC. All eight bits provide the GMII transmit data byte. For the lower speed MII operation, only bits[3:0] are used. The validity of the data is qualified with phy_txen_o and phy_txer_o. Synchronous to phy_txclk_o. |
emac_phy_txen_o | PHY Transmit Data Enable |
Out |
1 |
This signal is driven by the EMAC and is used in GMII mode. When driven high, this signal indicates that valid data is being transmitted on the clk_tx_o bus. |
emac_phy_txer_o | PHY Transmit Error |
Out |
1 |
This signal is driven by the EMAC and when high, indicates a transmit error or carrier extension on the phy_txd bus. It is also used to signal low power states in Energy Efficient Ethernet operation. |
emac_rst_clk_tx_n_o | Transmit Clock Reset output |
Out |
1 |
Transmit clock reset output to the FPGA fabric, which is the internal synchronized reset to clk_tx_int output from the EMAC. May be used by logic implemented in the FPGA fabric as desired. The reset pulse width of the rst_clk_tx_n_o signal is three transmit clock cycles. |
emac_clk_rx_i | Receive Clock |
In |
1 |
Receive clock from external PHY. For GMII, the clock frequency is 125 MHz. For MII, the receive clock is 25 MHz for 100 Mbps and 2.5 MHz for 10 Mbps. |
emac_phy_rxd_i[7:0] | PHY Receive Data |
In |
8 |
This is an eight-bit receive data bus from the PHY. In GMII mode, all eight bits are sampled. The validity of the data is qualified with phy_rxdv_i and phy_rxer_i. For lower speed MII operation, only bits [3:0] are sampled. These signals are synchronous to phy_clk_rx_i. |
emac_phy_rxdv_i | PHY Receive Data Valid |
In |
1 |
This signal is driven by PHY. In GMII mode, when driven high, it indicates that the data on the phy_rxd bus is valid. It remains asserted continuously from the first recovered byte of the frame through the final recovered byte. |
emac_phy_rxer_i | PHY Receive Error |
In |
1 |
This signal indicates an error or carrier extension (GMII) in the received frame. This signal is synchronous to phy_clk_rx_i. |
emac_rst_clk_rx_n_o | Receive clock reset output. |
Out |
1 |
Receive clock reset output. The reset pulse width of the rst_clk_rx_n_o signal is three transmit clock cycles. |
emac_phy_crs_i | PHY Carrier Sense |
In |
1 |
This signal is asserted by the PHY when either the transmit or receive medium is not idle. The PHY de-asserts this signal when both transmit and receive interfaces are idle. This signal is not synchronous to any clock. |
emac_phy_col_i | PHY Collision Detect |
In |
1 |
This signal, valid only when operating in half duplex, is asserted by the PHY when a collision is detected on the medium. This signal is not synchronous to any clock. |