Contents
What is DCM in Xilinx?
The Digital Clock Manager (DCM) primitive in Xilinx FPGA parts is used to implement delay locked loop, digital frequency synthesizer, digital phase shifter, or a digital spread spectrum. The digital clock manager module is a wrapper around the DCM primitive which allows it to be used in the EDK tool suite.
What is Mmcm and PLL?
The PLL and MMCM share very similar functionality but are not identical. Due to some subtle functionality differences and the requirement for different settings, a separate PLL reference design is provided. This allows the user to dynamically change the MMCM or PLL clock outputs while the design is running.
What is clock management tiles?
The clock management tiles (CMT) provide clock frequency synthesis, deskew, and jitter filtering functionality. Global clock trees allow clocking of synchronous elements across the device. • I/O and regional clock trees allow clocking of up to three vertically adjacent clock regions.
What are DCM’s why they are used?
applications. DCMs optionally multiply or divide the incoming clock frequency to synthesize a new clock frequency. DCMs also eliminate clock skew, thereby improving system performance. Similarly, a DCM optionally phase shifts the clock output to delay the incoming clock by a fraction of the clock period.
What are DCM in FPGA?
A digital clock manager (DCM) is an electronic component available on some field-programmable gate arrays (FPGAs) (notably ones produced by Xilinx). A digital clock manager is useful for manipulating clock signals inside the FPGA, and to avoid clock skew which would introduce errors in the circuit.
What is Dynamic Reconfiguration Port?
Dynamic Reconfiguration port (DRP) The Dynamic reconfiguration port that is an integral part of each functional block which greatly simplifies the process of reconfiguration. This allows the user to dynamically change the clock outputs while the design is running.
What is a global clock line?
To get that working properly, FPGA manufacturers provide special internal wires called “global routing” or “global lines”. They allow distributing the clock signal all over the FPGA with a low skew (i.e. the clock signal appears almost simultaneously to all the flip-flops).
How does a delay-locked loop work?
The delay-locked loop (DLL) is a circuit fed by a reference clock that attempts to find the period of that reference clock by adjusting the delay of a variable delay buffer in a feedback loop. The loop is locked when the delayed clock signal matches the incoming clock signal.
Can a FPGA have DCM and PLL?
Some FPGAs have both DCM (Digital Clock Manager) and PLL (Phase Lock Loop) for use in internal clock generation. Xilinx Spartan-6 FPGA Clocking Resources UG382 (v1.10) documentation describes a number of features for DCM:
What’s the difference between a PLL and mmcm?
So basically, the MMCM is just a PLL with a few extra cool features: The 1st link says “The PLL is organized similar to the MMCM with exceptions noted in the Figure 1 block diagram and in the subsequent tables.” THe table shows (MMCM only)in numerous outputs. Those are just the evolution in clock management from DCM to PLL to MMCM in xilinx parts.
What’s the difference between a DCM and a DLL?
Xilinx use the term DCM for their enhancement to what they used to call a DLL, or Delay Locked Loop. This (DLL) was a tapped delay line fed from the original clock signal, by selecting different taps, you could get different delays on the output clock signal.
What is the clocking debug guide for Xilinx FPGAs?
This Clocking Debug Guide directs you through the clocking debug steps, and provides best practices and tips in using the DCM and PLL. This guide contains the following sections: The purpose of this guide is to assist customers with common problems they face when using the clocking resources found in Xilinx FPGAs.