【FPGA】[VRFC 10-3236] concurrent assignment to a non-net ‘data_out’ is not permitted
报错如下：
[VRFC 10-3236] concurrent assignment to a non-net ‘data_out’ is not permitted [“F:/fpgaWork/project_test_gamma/project_test_gamma.srcs/sources_1/new/test_coe.v”:82]
解决方法：
这种问题，大多数是因为变量的wire 或reg 类型不匹配引起的。 主要有两种： 1）源文件调用（例化）别的模块时候，顶层文件（模块）与被例化的文件（模块），变量类型不统一
2）testbench 中，与被测试的文件（模块）中，在变量的wire 或reg 说明上也容易出错，要注意。
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Concurrent assignment to a non-net '_' is not permitted
I’m getting the error:
What am I doing wrong?
March 2, 2023 at 11:55 am
In the ex1 module, you are trying to make a concurrent assignment to a non-net variable ‘a’ and ‘b’. Non-net variables are not allowed to be used in concurrent assignments. You should use ‘wire’ instead of ‘reg’ for ‘a’ and ‘b’. Also, the ternary operator should be modified to assign the value of ‘c’ instead of ‘a’ when the condition is true.
Here is the corrected code:
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Vivado Verilog Simulation error: concurrent assignment to a non-net is not permitted
- Thread starter ALUW
- Start date Dec 4, 2022
- Dec 4, 2022
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Error: HDL-Complier-661 Non-net port cannot be mode of input
I'm trying to develop a Verilog code for right shifting as a part of Floating Point ALU. I'm getting the following error in line 7:
Error: HDL-Complier-661 .... Non net port cannot be mode of input
Please tell me what my error is and provide me with corrected code.
3 Answers 3
Verilog does not allow input ports declared as a variable with a data type (SystemVerilog does).You can remove that line. I also suggest using a simpler form of port declarations that only mentions each port name once instead of up to three times (called ANSI style in the IEEE LRM)
- \$\begingroup\$ This worked . Note that we have to use comas, instead if semicolons. module right_shifter( input [3:0] small_mant, input [2:0] shift_amt, output reg [5:0] shifted_mant ); \$\endgroup\$ – Abhishek Chunduri May 7, 2020 at 10:26
You've declared your port as input [3:0] small_mant; - this means you are declaring an input to the module, which must be of a net type (a.k.a. a wire ).
However you then re-declare your input port as reg [3:0] small_mant; which is a variable data type ( reg ), and therefore not a net type.
You cannot, and in fact never need to, declare an input as a reg , so simply remove that line.
The corrected code :-
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verilog Error in If statement. (reg) is not a constant. Target <reg> of concurrent assignment or output port connection should be a net type
I'm making a 8Bit select adder with 4bit adder.
When i try to test this code.
i got a 2 error.
First one is "coutL is not a constant"
Second one is "Target of concurrent assignment or output port
connection should be a net type."
Can anyone help me?
The following statement makes no sense with semicolon after it:
I guess the following begin .. end were intended to go with the previous always block. They did not because of the semicolon. In any case, instantiating of modules inside such a block is illegal in verilog, it should be done outside the block and outside of begin/end:
Both, stand-alone begin/end and if statement represent a generate block in modern verilog. So, the following is a part of the generate block:
But such blocks only operate with constants. So countL must be a constant, i.e. a parameter . It is a reg, therefore, there is an error.
Again, it seems that you intended this as a part of the always block. assign statements within such a block are a very special verilog constructs and should not be used without a very good understanding of what they do.
My guess is that you intended something like the following:
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The trailing comma in a port list is illegal. Change: output wire c, to: output wire c. It is illegal to assign a value to an input port inside a module. This is illegal: a=1'b1. Assuming it was a typo to use a there, and you really meant to type c, you should change: assign c=(a>b)?(a=1'b1):(c=1'b0);
Only clk is a input: module cpu_1(clk, inst_out, m1_out, QA, QB, IMME, WREG, M2REG, WMEM, ALUIMM, REGR1, m1_select, ALUC); input clk; Skip to main content ... What is "concurrent assignment to a non-net <port_name> is not permitted" Verilog simulation error? Ask Question Asked 3 years, 7 ... Concurrent assignment to a non-net is not permitted. 0.
Another thing to note is when instantiating verilog primitives, the portmapped signals which are used should be of net datatype. I tried this test case with above declaration and able to simulate it properly with expected output P[0] from AND gate.
Module puts need to be connected to a net-type (ex wire). However a wire cannot be assigned in a procedural code (ex always block). So you need to think how to assign some bits to from a module and other from procedural. \$\endgroup\$
For the following code,I get several errors: 1)Target <mem> of concurrent assignment or output port connection should be a net type. 2)in_d0_ is not a constant How this issue can be solved? module module_cell44( in_d0,in_d1,in_d2,in_d3,out_61,out_68,clk ); parameter DATA_WIDTH = 16; parameter ADDR_WIDTH = 8; parameter ADDR_DEPTH = 1 << ADDR_WIDTH; // Interfaces input clk; input [DATA_WIDTH - 1 ...
Concurrent assignment to a non-net a is not permitted . ERROR:Simulator:778 - Static elaboration of top level Verilog design unit(s) in library work failed ... (m2),.m3(m3),.a(a),.b(b),.c(c),.en(en),.clka(clk)); The connections are described as: .portInModule(signalToConnect). By doing it this way it doesn't matter what order they appear ...
I got 2 errors [Synth 8-1852] concurrent assignment to a non-net DOUT_O is not permitted. I got [Synth 8-6735] net type must be explicitly sepecified for 'CLK_I' when default_nettype is none and finally I got [Synth 8-2442] non-net port CLK_I cannot be of mode input. All these errors appear in a generated file called ltlib_v1_0_v1_rfs.v which ...
My testbench instantiation aligns to the former and not the latter and hence my post implementation simulations were not running. If I had instantiated the UUT in the testbench using named ports i.e. mealy_patrn (.detect(detect) .data_in(data_in) .clk(clk_1) .rst(rst)); this would no longer be an issue (as it is now not). Is this a Vivado tool ...
文章浏览阅读2.2w次，点赞17次，收藏53次。一个案例：待测试模块输入输出为：TestBench测试文件为：一仿真，报错 concurrent assignment to a non-net 'xxxx' is not permitted原因分析：对于待测试模块的输出 "dout_7888"，在编写测试文件的时候，不能将与之交联的"dout_7888"定义为 reg 型，须改为 wire 型。
一个案例： 待测试模块输入输出为： TestBench测试文件为： 一仿真，报错 concurrent assignment to a non-net 'xxxx' is not permitted 原因分析： 对于待测试模块的输出 "dout_7888"，在编写测试文件的时候，不能将与之交联的"dout_7888"定义为 reg 型，须改为 wire 型。 对于模块中的输出来说 即，不能以 TestBench ...
Non-net variables are not allowed to be used in concurrent assignments. You should use 'wire' instead of 'reg' for 'a' and 'b'. Also, the ternary operator should be modified to assign the value of 'c' instead of 'a' when the condition is true.
It is illegal to make a procedural assignment (within an block) to a . You need to declare the signal as : logic [1:0] nextstate; Do this for all signals which are assigned in the block. You must also do this for the ports which are assigned in the block. For example: output logic cs;
I replaced CLK_100MHZ by clk_100MHZ but Now I am getting following errors.
The types reg, wire only apply in the current module and are not carried over port connections. Remember the choice of wire or reg is for the simulator not indicative of the hardware. In SystemVerilog the majority of wire/reg can be replaced with logic. The only place this does not work is for tristate busses then you should use tri.
Please include at least the portlist definition for sub-module Mul_demul. My guess is on this sub-module, port "s1" is an output. Or since you're using port connection by position, instead of port connection by name, and you're connecting up to the wrong ports.
Dec 4, 2022. #1. ALUW Asks: Vivado Verilog Simulation error: concurrent assignment to a non-net is not permitted. I am new to using verilog and am getting the errors concurrent assignment to a non-net 'sample' is not permitted, concurrent assignment to a non-net 'rst' is not permitted, and concurrent assignment to a non-net 'rst' is not permitted.
You've declared your port as input [3:0] small_mant; - this means you are declaring an input to the module, which must be of a net type (a.k.a. a wire).. However you then re-declare your input port as reg [3:0] small_mant; which is a variable data type (reg), and therefore not a net type.. You cannot, and in fact never need to, declare an input as a reg, so simply remove that line.
Concurrent assignment to a non-net is not permitted. 0. What is "concurrent assignment to a non-net <port_name> is not permitted" Verilog simulation error? 1. SV ERROR: driven via a port connection, is multiply driven. 1. Output port continuous assignment problem. Hot Network Questions
谢谢，按照您的方法sim已经不报错了，但是仿真界面的值都是不定态，修改时序后，有了新的错误，我会继续开一个新帖子。