Visible to Intel only — GUID: kbw1689204908359
Ixiasoft
Visible to Intel only — GUID: kbw1689204908359
Ixiasoft
2.2.1.1. Clocks
The PHY Lite for Parallel Interfaces Intel® FPGA IP for Agilex™ 5 E-Series sources an external reference clock from a dedicated clock pin to the PLL inside the IP. This PLL provides four clock domains for the output and input paths.
Clock Domain | Description |
---|---|
Interface clock | This is the clock frequency of the external device connected to the FPGA I/Os. |
VCO clock | The PLL generates this clock internally. The input and output paths use the VCO clock to generate interpolator delays that compensates for PVT variations. |
PHY clock | The IP uses this clock internally for PHY circuitry. |
Core clock | The IP generates this clock internally and uses it for all transfers between the FPGA core fabric and I/O banks. The clock phase alignment (CPA) circuitry keeps the clock in phase with the PHY clock for transfers between the core and the periphery. |
The clock frequency of user logic and other clocks are derived from the interface clock frequency based on predetermined PHYLITE_IN_RATE and PHYLITE_OUT_RATE parameters as shown in the following equation and are summarized in the following table. The calculated core clock frequency is fixed based on the selected interface clock frequency and displayed in the IP parameter editor as a grayed-out value as shown in the following figure.
Interface Frequency (MHz) | PHYLITE_IN_RATE (Core Clock Rate) | PHYLITE_OUT_RATE (VCO Frequency Multiplier Factor) | VCO Clock Frequency (MHz) | PHY Clock Frequency (MHz) | Core Clock Frequency (MHz) |
---|---|---|---|---|---|
600-1250 | 4 | 1 | 600-1250 | 300-625 | 150-312.5 |
300-600 | 2 | 2 | 600-1200 | 300-600 | 150-300 |
150-300 | 1 | 4 | 600-1200 | 300-600 | 150-300 |
- For the boundary frequencies of 300 MHz, PHYLITE_IN_RATE = 1 and PHYLITE_OUT_RATE = 4.
- For the boundary frequencies of 600 MHz, PHYLITE_IN_RATE = 2 and PHYLITE_OUT_RATE = 2.