concurrent assignment to a non
时间: 2023-04-23 14:04:17 浏览: 124
-volatile variable and volatile read/write may encounter torn read
并发地给非 volatile 变量赋值和读写 volatile 变量可能会遇到撕裂读。
相关问题
concurrent assignment to a non-net
In Verilog, a non-net refers to a variable that is not a wire or a register, but rather a constant or a parameter. Concurrent assignment refers to the assignment of a value to a variable using the "=" operator in a module outside of any procedural blocks (such as always or initial blocks).
A concurrent assignment to a non-net is not allowed in Verilog. This is because a non-net does not have a storage element and cannot hold a value assigned to it. Instead, it is typically used as a constant or a parameter that is available for use in the module.
To assign a value to a non-net, it should be done within a procedural block using the appropriate assignment operator (such as "<=" for registers or "assign" for wires). Alternatively, the value can be passed as an argument to the module using the parameter keyword.
For example:
module my_module #(parameter WIDTH = 8) (
input clk,
input [WIDTH-1:0] data_in,
output [WIDTH-1:0] data_out
);
// This is a non-net parameter
parameter ADD_VALUE = 5;
// This is a register that can be assigned using the "=" operator within an always block
reg [WIDTH-1:0] register_data;
always @(posedge clk) begin
register_data <= data_in + ADD_VALUE;
end
// This is a wire that can be assigned using the "assign" keyword
assign data_out = register_data;
endmodule
In this example, ADD_VALUE is a non-net parameter that is used in the always block to add a constant value to the input data. The register_data variable is assigned using the "=" operator within the always block. The data_out wire is assigned using the "assign" keyword.
ERROR: concurrent assignment to a non-net 'add_cnt_1ms' is not permitted in PWM.v(35)
这个错误可能是因为在Verilog代码中,您尝试同时对同一个变量进行多次赋值。在 Verilog 中,不能将非网络类型的变量同时分配给多个值。您需要确保在代码中只有一个地方对该变量进行赋值。
在这种情况下,错误是在PWM.v文件的第35行发生的。您需要仔细检查代码并确保在该行之前或之后没有其他地方对add_cnt_1ms进行分配。如果需要在多个地方使用该变量,请考虑使用寄存器或网络类型变量来避免这个错误。
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