5.1. Clock Signals
Signal Name | Direction | Width | Description | PHY Configurations |
---|---|---|---|---|
tx_clkout | Output | 1 | GMII TX clock, derived from tx_pll_refclk. Provides 156.25 MHz timing reference for 2.5G; 62.5 MHz for 1G, 100M, and 10M. |
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rx_clkout | Output | 1 | GMII RX clock, derived from tx_pll_refclk. Provides 156.25 MHz timing reference for 2.5G; 62.5 MHz for 1G, 100M, and 10M. This clock is internally connected to tx_clkout with rate match FIFO. |
|
csr_clk | Input | 1 | Clock for the control and status interface. Altera recommends 100 MHz - 125 MHz for this clock. | All MGBASE and NBASE variants |
xgmii_tx_coreclkin | Input | 1 | TX clock for XGMII logic before phase compensation FIFO. Provides a 312.5 MHz timing reference for the 10M/100M/1G/2.5G/5G/10G (USXGMII) mode and 156.25 MHz timing reference for MGBASE 10G mode. This clock should be synchronous to o_clk_pll. |
|
xgmii_rx_coreclkin | Input | 1 | RX clock for XGMII logic after rate matcher. Provides a 312.5 MHz timing reference for the 10M/100M/1G/2.5G/5G/10G (USXGMII) mode and 156.25 MHz timing reference for MGBASE 10G mode. This clock should be synchronous to o_clk_pll. |
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tx_pll_refclk_p |
Input | 1 | Reference clock for each of the TX PLL. |
|
rx_cdr_refclk_p |
Input | 1 | Provides 156.25 MHz/312.5 MHz reference clock for the RX CDR. |
MGBASE variants only |
i_system_pll_clk | Input | 1 | To be connected to the GTS System PLL Clock Intel® FPGA IP PLL output. |
|
i_system_pll_lock | Input | 1 | System PLL locked signal. | All MGBASE and NBASE variants |
latency_measure_clk | Input | 1 | Sampling clock for measuring the latency of the 16-bit GMII datapath. This clock operates at 80 MHz ± 100 ppm and is available only when the IEEE 1588 feature is enabled. | MGBASE variants:
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latency_sclk | Input | 1 | Sampling clock for measuring the latency of the transceiver AIB datapath. The clock period is 4.375 ns for 2.5G and 1G/2.5G (MGBASE), 6.5 ns for 10M/100M/1G/2.5G/5G/10G (USXGMII) It is available only when the IEEE 1588 feature is enabled. |
|
rx_pma_clkout | Output | 1 | Recovered clock from CDR, operates at the following frequency:
10M/100M/1G/2.5G/5G/10G (USXGMII) speed mode:
Other speed modes:
|
All MGBASE and NBASE variants |
i_pma_cu_clk | Input | 1 | PMA Control Unit clock, one per GTS bank for each side of the device. This clock port must be connected from the GTS Reset Sequencer Intel® FPGA IP. The clock frequency is 250 MHz. | All MGBASE and NBASE variants |
o_clk_pll | Output | 1 | Clock derived from the System PLL associated with the Ethernet Port. The frequency is the system PLL frequency divided by 2. It should be used in the user logic to generate xgmii_*_coreclkin for a synchronous user application. | NBASE variants: 10M/100M/1G/2.5G/5G/10G (USXGMII) |
i_clk_pll | Input | 1 | This clock signal is unused. Tie this signal to ground. | NBASE variants: 10M/100M/1G/2.5G/5G/10G (USXGMII) |
gmii8b_tx_clkout | Output | 1 | GMII TX clock, derived from tx_pll_refclk. Provides 312.5 MHz timing reference for 2.5G; 125 MHz for 1G, 100M, and 10M. | GMII/MII transmit clock to HPS |
gmii8b_rx_clkout | Output | 1 | GMII RX clock, derived from tx_pll_refclk. Provides 312.5 MHz timing reference for 2.5G; 125 MHz for 1G, 100M, and 10M. | GMII/MII receive clock to HPS |
gmii8b_tx_clkin | Input | 1 | TX out clock. | GMII/MII transmit clock from HPS |