"使用DCM消除时钟Skew" 时钟Skew是一个常见的问题，在数字电路设计中，它会对系统的可靠性和稳定性产生影响。时钟Skew是指时钟信号在不同寄存器之间的延时差异，这种延时差异会导致系统的不稳定性和可靠性问题。为了解决这个问题，数字电路设计中常用的方法是使用DCM（Digital Clock Management）和BUFG（Buffer）组合来消除时钟Skew。 什么是DCM？DCM是一个数字时钟管理模块，它内部结构是一个DLL（Delay Lock Loop）结构，用于调整时钟偏移量的延时线。DCM的参数中有一个PHASESHIFT（相移），可以从0变到255，这意味着DCM内部有256个延时线。DCM总是将输入时钟Clkin和反馈时钟Clkfb相比较，如果它们的延时差不等于所设置的PHASESHIFT，DCM就会改变Clkin和Clk_1x之间的延时线数目，直到相等为止。 如何使用DCM？DCM一般和BUFG配合使用，要加上BUFG，应该是为了增强时钟的驱动能力。DCM的一般使用方法是，将其输出Clk_1x接在BUFG的输入引脚上，BUFG的输出引脚反馈回来接在DCM的反馈时钟脚CLKFB上。 使用DCM可以消除时钟Skew。时钟Skew是指时钟驱动不同的寄存器时，由于寄存器之间可能会隔得比较远，导致时钟到达不同的寄存器的时间可能会不一样，这个时间差称为时钟Skew。使用DCM可以消除时钟Skew，因为DCM可以调整Clkin和Clk_1x之间的延时线数目，使得Clkin和Clk_1x的相位相等，从而消除时钟Skew。 时钟Skew的概念。时钟Skew实际上指的是时钟驱动不同的寄存器时，导致时钟到达不同的寄存器的时间可能会不一样，这个时间差称为时钟Skew。这种时钟Skew可以通过时钟树来解决，也就是使时钟布线形成一种树状结构，来解决时钟Skew问题。 FPGA芯片中时钟Skew的问题。FPGA芯片中，时钟Skew的问题已经被FPGA的时钟方案树解决，但是FPGA的设计不可能永远只在内部做事情，它必然和外部交换数据。为了解决这个问题，需要使用DCM+BUFG来消除时钟Skew。 使用DCM可以消除时钟Skew，解决时钟Skew问题，提高系统的可靠性和稳定性。

这是一个外国人写的图片变形的示例,图片可以任意变形

jitter和skew介绍与区别

Specifically, this book deals in depth with the following issues: • A methodology for simultaneous non-zero clock skew scheduling and design of the topology of the clock distribution network. This methodology is based on the pioneering works of Friedman [1] and Fishburn [2], and builds on Linear Programming (LP) solution techniques. The non-zero clock skew scheduling of circuits with level-sensitive latches and for multi-phase clock signals is formulated as a LP problem. The simultaneous clock scheduling and clock tree topology synthesis problem is formulated as a mixed-integer linear programming problem that can be solved efficiently. The proposed algorithms have been evaluated on a variety of benchmark and industrial circuits and synchronous performance improvements of well above 60% have been demonstrated. • For those cases where reliable circuit operation and production yield are the highest level priorities, an alternative problem formulation is developed. This formulation is based on a quadratic (hence the QP—quadratic programming) measure, or cost function, of the tolerance of a clock schedule to parameter variations. A mathematical framework is presented for solving the constrained and bounded QP problem. A constrained version of the problem is iteratively solved using the Lagrange multipliers method. As these research issues are topics of great practical importance for input/output (I/O) interfacing and Intellectual Property (IP) blocks, explicit clock delay and skew requirements are fully integrated into the mathematical model described here. The theoretical derivation of the limits on the improvements on the clock period available through clock skew scheduling. The theoretical derivation is performed by identifying the limits for three local data path topologies. A methodology to mitigate the limitation of clock skew scheduling for a reconvergent path system is presented. The methodology involves delay insertion on some data paths of the reconvergent syst

1、cocoscreator使用mask+skew的方法实现搓牌功能 2、这是以前项目中的模块，现在提取出来，当初摸索着写的难免有弯路，仅供学习参考。creator版本为1.9.3，稍微做修改就可以用2.0及新版本使用。 3、效果图请移步：https://pan.baidu.com/s/11v096Bbi3PmqbAEL7Uonew#list/path=/我的分享/CSDN/CardDemo 4、如有疑问，请留言。