Agilex™ 7 Clocking and PLL User Guide: F-Series and I-Series
ID
683761
Date
11/28/2024
Public
1. Agilex™ 7 FPGA F-Series and I-Series Clocking and PLL Overview
2. F-Series and I-Series Clocking and PLL Architecture and Features
3. F-Series and I-Series Clocking and PLL Design Considerations
4. Clock Control Intel® FPGA IP Core
5. IOPLL Intel® FPGA IP Core
6. IOPLL Reconfig Intel® FPGA IP Core
7. Agilex™ 7 Clocking and PLL User Guide: F-Series and I-Series Archives
8. Document Revision History for the Agilex™ 7 Clocking and PLL User Guide: F-Series and I-Series
2.2.1. PLL Features
2.2.2. PLL Usage
2.2.3. PLL Locations
2.2.4. PLL Architecture
2.2.5. PLL Control Signals
2.2.6. PLL Feedback Modes
2.2.7. Clock Multiplication and Division
2.2.8. Programmable Phase Shift
2.2.9. Programmable Duty Cycle
2.2.10. PLL Cascading
2.2.11. PLL Input Clock Switchover
2.2.12. PLL Reconfiguration and Dynamic Phase Shift
2.2.13. PLL Calibration
3.1. Guidelines: Clock Switchover
3.2. Guidelines: Timing Closure
3.3. Guidelines: Resetting the PLL
3.4. Guidelines: Configuration Constraints
3.5. Guidelines: I/O PLL Reconfiguration
3.6. Clocking Constraints
3.7. IP Core Constraints
3.8. Guideline: Achieving 5% Duty Cycle for fOUT_EXT ≥ 300 MHz Using tx_outclk Port from LVDS SERDES Intel® FPGA IP
6.1. Release Information for IOPLL Reconfig Intel® FPGA IP
6.2. Implementing I/O PLL Reconfiguration in the IOPLL Reconfig IP Core
6.3. IOPLL Reconfig IP Core Reconfiguration Modes
6.4. Avalon® Memory-Mapped Interface Ports in the IOPLL Reconfig IP Core
6.5. Address Bus and Data Bus Settings
6.6. Design Example
2.2.6.6. External Feedback Mode
In external feedback (EFB) mode, the output of the M counter (fbout) feeds back to the PLL fbin input (using a trace on the board) and becomes part of the feedback loop. EFB mode is only supported for I/O bank I/O PLL, not supported for fabric-feeding I/O PLL.
One of the dual-purpose external clock outputs becomes the fbin input pin in this mode. The external feedback input pin, fbin is phase-aligned with the clock input pin. Aligning these clocks allows you to remove clock delay and skew between devices.
In EFB mode, you must use the same I/O standard on the input clock, feedback input, and clock outputs.
Figure 15. Example of Phase Relationship Between the PLL Clocks in EFB Mode