F-Tile Low Latency 50G Ethernet Intel® FPGA Soft-IP User Guide
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7.8. Clock Signals
The F-tile Reference and System PLL Clocks Intel® FPGA IP is required to generate i_clk_ref and i_clk_sys input clocks that drive this IP core.
A 390.625 MHz transmit clock (clk_txmac) is derived from Tx clock divider of Ethernet_F-Tile IP. This clock is guaranteed stable when tx_lanes_stable is high.
A 390.625MHz receive clock (clk_rxmac) is derived from Rx clock divider of eth_f IP. This clock is guaranteed stable when rx_pcs_ready is high.
The Avalon® MM clock (clk_status) is nominally 100MHz but can be as high as 125MHz.
| Signal Name | Direction | Width | Nominal Frequency | Description |
|---|---|---|---|---|
| i_clk_ref | Input | 1 | 156.25 MHz transceiver reference clock. You must specify this frequency in the F-Tile Reference and System PLL Clock Intel® FPGA IP FGT refclk frequency IP parameter. Connect this signal to the out_refclk_fgt_<i> output signal of the F-Tile Reference and System PLL Clocks Intel® FPGA IP. |
|
| i_clk_sys | Input | 1 | 805.6640625 MHz Ethernet system clock. You must specify this frequency in the F-Tile Reference and System PLL Clock Intel® FPGA IP Mode of system PLL IP parameter. Connect this signal to the out_systempll_clk_<i> signal of the F-Tile Reference and System PLL Clocks Intel® FPGA IP. |
|
| clk_txmac | Output | 1 | 390.625 MHz | Clock for TX section |
| clk_rxmac | Output | 1 | 390.625 MHz | Clock for TX section |
| clk status | Input | 1 | 100 MHz | Avalon® MM interface clock |
| reconfig_clk | Input | 1 | 100 MHz | Transceiver reconfiguration clock |