1. Agilex™ 3 Clocking and PLL Overview
2. Agilex™ 3 Clocking and PLL Architecture and Features
3. Agilex™ 3 Clocking and PLL Design Considerations
4. Clock Control Altera™ FPGA IP Core
5. IOPLL FPGA IP
6. I/O PLL Reconfiguration
7. Document Revision History for the Clocking and PLL User Guide: Agilex™ 3 FPGAs and SoCs
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
6.1.1. Release Information for EMIF Calibration IP
6.1.2. Setting Up the IOPLL FPGA IP
6.1.3. Setting Up the EMIF Calibration IP
6.1.4. Connectivity Between IOPLL FPGA IP and EMIF Calibration IP
6.1.5. Axilite Interface Ports in the EMIF Calibration IP
6.1.6. Reconfiguration Guideline for HSIO I/O PLLs
6.1.7. Design Example for HSIO I/O PLL Reconfiguration
6.2.2.1. Read and Write Operations via Avalon® Memory-Mapped Interface
6.2.2.2. Enabling Reconfiguration for The Desired I/O PLL
6.2.2.3. Clearing off Calibration Statuses
6.2.2.4. Reconfiguring The I/O PLL
6.2.2.5. Enabling Recalibration for HVIO PLLs
6.2.2.6. Requesting Recalibration of I/O PLL
6.2.2.7. Clock Gating (Optional)
2.2.5.2. Locked
The locked signal port of the IP for the I/O PLL is locked. The IOPLL IP drives locked signal high when the PLL acquires lock.
The lock detection circuit provides a signal to the core logic. The signal indicates when the feedback clock locks onto the reference clock both in phase and frequency.
PLL loses lock if the input reference clock stops toggling. When PLL loses lock, the output of the PLL starts drifting out of the desired frequency. The downstream logic must be held inactive when PLL has lost lock.