1. Intel® MAX® 10 Clocking and PLL Overview
2. Intel® MAX® 10 Clocking and PLL Architecture and Features
3. Intel® MAX® 10 Clocking and PLL Design Considerations
4. Intel® MAX® 10 Clocking and PLL Implementation Guides
5. ALTCLKCTRL Intel® FPGA IP References
6. Avalon ALTPLL Intel® FPGA IP References
7. Avalon ALTPLL RECONFIG Intel® FPGA IP References
8. Internal Oscillator Intel® FPGA IP References
9. Intel® MAX® 10 Clocking and PLL User Guide Archives
10. Document Revision History for the Intel® MAX® 10 Clocking and PLL User Guide
2.3.1. PLL Architecture
2.3.2. PLL Features
2.3.3. PLL Locations
2.3.4. Clock Pin to PLL Connections
2.3.5. PLL Counter to GCLK Connections
2.3.6. PLL Control Signals
2.3.7. Clock Feedback Modes
2.3.8. PLL External Clock Output
2.3.9. ADC Clock Input from PLL
2.3.10. Spread-Spectrum Clocking
2.3.11. PLL Programmable Parameters
2.3.12. Clock Switchover
2.3.13. PLL Cascading
2.3.14. PLL Reconfiguration
3.3.1. Guideline: PLL Control Signals
3.3.2. Guideline: Connectivity Restrictions
3.3.3. Guideline: Self-Reset
3.3.4. Guideline: Output Clocks
3.3.5. Guideline: PLL Cascading
3.3.6. Guideline: Clock Switchover
3.3.7. Guideline: .mif Streaming in PLL Reconfiguration
3.3.8. Guideline: scandone Signal for PLL Reconfiguration
6.1.1. Operation Modes Parameter Settings
6.1.2. PLL Control Signals Parameter Settings
6.1.3. Programmable Bandwidth Parameter Settings
6.1.4. Clock Switchover Parameter Settings
6.1.5. PLL Dynamic Reconfiguration Parameter Settings
6.1.6. Dynamic Phase Configuration Parameter Settings
6.1.7. Output Clocks Parameter Settings
2.1.7. Clock Enable Signals
The Intel® MAX® 10 devices support clkena signals at the GCLK network level. This allows you to gate off the clock even when a PLL is used. After reenabling the output clock, the PLL does not need a resynchronization or relock period because the circuit gates off the clock at the clock network level. In addition, the PLL can remain locked independent of the clkena signals because the loop-related counters are not affected.
Figure 5. clkena Implementation
Note: The clkena circuitry controlling the C0 output of the PLL to an output pin is implemented with two registers instead of a single register.
Figure 6. Example Waveform of clkena Implementation with Output EnableThe clkena signal is sampled on the falling edge of the clock (clkin). This feature is useful for applications that require low power or sleep mode.
The clkena signal can also disable clock outputs if the system is not tolerant to frequency overshoot during PLL resynchronization.