GEM requires the following clocks:
The following table lists the required frequencies of the transmit clock.
MAC Speed Mode (Mbps) | gtx_clk (MHz) | tx_clk (MHz) | ||
---|---|---|---|---|
SGMII | GMII | SGMII | MII | |
10 | 125 | N/A | 1.25 | 2.5 |
100 | 125 | N/A | 12.5 | 25 |
1000 | 125 | 125 | 125 | 125 |
The following table lists the required frequencies of the receive clock.
MAC Speed Mode (Mbps) | pcs_rx_clk (MHz) | rx_clk (MHz) | ||
---|---|---|---|---|
SGMII | GMII/MII | SGMII | GMII/MII | |
10 | 125 | N/A | 1.25 | 2.5 |
100 | 125 | N/A | 12.5 | 25 |
1000 | 125 | N/A | 62.5 | 125 |
For more information about GEM Clocking, see PolarFire FPGA and PolarFire SoC FPGA Clocking Resources User Guide .