Verilog-Latch的产生 避免latch的产生 latch的简介 latch其实就是锁存器,是一种在异步电路系统中,对输入信号电平敏感的单元,用来存储信息。 锁存器在数据未锁存时,输出端的信号随输入信号变化,就像信号通过一个缓冲器,一旦锁存信号有效,则数据被锁存,输入信号不起作用。因此,锁存器也被称为透明锁存器,指的是不锁...
触发器:flipflop,锁存器:latch 对于这个认识,我写了几行Verilog代码 代码如下 `module dff_latch_top( input clk, input ena, input [3:0] a, input [3:0] b, output reg [3:0] c, output reg [3:0] d, output reg [3:0] e, output reg [3:0] f, output reg [3:0] g ); //c ...
然而,我们常常会遇到由于逻辑定义不完整综合出LATCH的情况。在代码包含always@(*)时,一般情况下会综合出LUT,但假如没有将if/else中所有case的赋值情况写完整,编译器就会综合出LATCH,以下是一段综合出LATCH的Verilog代码: module top_module ( input [15:0] scancode, output reg left, output reg down, output ...
这个问题倒不是太大,verilog2001语法中可以直接用 * 搞定了。顺便提一句,latch有弊就一定有利。在fpga的le中,总存在一个latch和一个d触发器,在支持ddr的ioe(iob)中也存在着一个latch来实现ddio。不过在我们平时的设计中,对latch还是要尽可能的敬而远之。 fpga设计要点之四:逻辑仿真仿真是fpga设计中必不可少...
源于《Verilog HDL 高级数字设计》—第二版 // SR LatchmoduleSR_Latch(inputS,R,outputregQ);regQ_n;always@(*)beginQ_n=!(S|Q);//均使用非阻塞赋值效果是一样的Q=!(R|Q_n);endendmodule Vivado-RTL级图表生成【SR锁存器】 2.2D锁存器(数据锁存器/透明锁存器) ...
Assume that you want to implement hierarchical Verilog code for this circuit, using three instantiations of a submodule that has a flip-flop and multiplexer in it. Write a Verilog module (containing one flip-flop and multiplexer) named top_module for this submodule. ...
[h=3]verilog hdl always construct warning at <location>: inferring latch(es) for variable "<name>", which holds its previous value in one or more paths through the always construct[/h] how can i write this code without getting this warning because i do ...
Assume that you want to implement hierarchical Verilog code for this circuit, using three instantiations of a submodule that has a flip-flop and multiplexer in it. Write a Verilog module (containing one flip-flop and multiplexer) named top_module for this submodule. ...
I have question about the verilog code causing Latch and not flip-flop. Your suggestions are welcome. I can add more register stage to this but that can affect the performance. I am not sure why the QuartusII synthesis tool is considering ReqInFifoDataIn[72] ...
case(scancode) 16'he06b: left = 1; 16'he072: down = 1; 16'he074: right = 1; 16'he075: up = 1; endcase end endmodule 代入HDLBits中验证: 麻烦的设计 如果不给默认值,我们可以这么设计: // synthesis verilog_input_version verilog_2001 ...