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Visible to Intel only — GUID: dxd1617022546402
Ixiasoft
3.7. Custom Cadence Generation Ports and Logic
When using system PLL clocking mode, you must enable the Custom cadence generation (CCG) ports and logic parameter for the use cases that Custom Cadence Generation Ports and Logic Use Cases describes. Enabling CCG logic ensures that the TX PMA interface FIFO does not overflow due to the over clocking of the datapath when using system PLL clocking mode.
Configuration | Datapath Clocking mode | System PLL Frequency | Enable Custom Cadence Generation (CCG) Ports and Logic |
---|---|---|---|
PMA Direct | PMA | N/A | No |
PMA Direct | System PLL | Equal to PMA parallel clock frequency. No PPM between PMA parallel clock frequency and system PLL frequency. That is, the same reference clock source for PMA and system PLL.35 | No |
PMA Direct | System PLL | Greater than the PMA parallel clock frequency. | Yes |
FEC Direct | System PLL | Equal to the PMA Parallel clock frequency. No PPM between PMA parallel clock frequency and system PLL frequency. That is, the same reference clock source for PMA and system PLL. | No |
FEC Direct | System PLL | Equal to the PMA Parallel clock frequency. PPM between PMA parallel clock frequency and system PLL frequency. That is, different reference clock for PMA and system PLL. | Yes |
FEC Direct | System PLL | Greater than the PMA parallel clock frequency. | Yes |
When you enable Custom cadence generation (CCG) ports and logic, the tx_cadence, tx_cadence_fast_clk, and tx_cadence_slow_clk ports are available in the F-Tile PMA/FEC Direct PHY Intel® FPGA IP. CCG logic uses the tx_cadence_fast_clk and tx_cadence_slow_clk inputs (does not monitor PMA Interface FIFO status), and generates a tx_cadence output signal. You must use tx_cadence to assert and de-assert the TX PMA Interface data valid bit. This bit is one of the bits in TX parallel data. Refer to Parallel Data Mapping Information.
Configuration | Enable TX Double Width Transfer | Recommended Connections |
---|---|---|
PMA Direct | Yes |
|
PMA Direct | No |
|
FEC Direct | Yes |
|