1 module example_module #(parameter SIZE = 8) ( 2 input wire [SIZE-1:0] data_in, 3 output reg [SIZE-1:0] data_out 4 ); 5 // ... 模块的实现 synchronous reset This is a Moore state machine with two states, one input,
A state machine is a sequential circuit that advances through a number of states. The examples provide the Verilog HDL codes to implement the following types of state machines.
4-State Moore State Machine The outputs of a Moore state machine depend only on the present state. The outputs are written only when the state changes (on the clock edge).Safe State Machine This example uses the syn_encoding synthesis attribute value safe to specify that the software...
RIGHT = 1, FALL = 2; 13 reg [1:0] state, next_state, pre_state; 14 15 always @(*) begin 16 case (state) 17 LEFT: begin 18 if (ground == 0) 19 next_state = FALL; // 掉下去 20 else if (bump
assign {ds,rd} = state[1:0]; endmodule 2. 三段式写法 三段式写法是在两段式的基础上加了输出的always模块。上面的example是一个典型的两段式写法。三段式写法相对于两段式,优势在于能实现在不插入额外时钟节拍的前提下实现寄存器输出。 Example:
The state machine should reset into a state where it begins searching for the input sequence 1101. Here is an example of the expected inputs and outputs. The 'x' states may be slightly confusing to read. They indicate that the FSM should not care about that particular input signal in that...
This example implements a clocked bidirectional pin in Verilog HDL. The value of OE determines whether bidir is an input, feeding in inp, or a tri-state, driving out the value b. bidir.v module bidirec (oe, clk, inp, outp, bidir); ...
SystemVerilog enumerated types are especially useful for coding state machines. An example of using an enumerated type as the state variable is shown below. typedef enum { IDLE = 2'b00, ACTIVE = 2'b01, DONE = 2'b10, XX = 'x
for placeholders. Placeholders with the // same ids are connected. // Example: /...
Example2: input a,b,c; reg e,d; always @(a or b or c or d) begin e=d&a&b; /*d在敏感电平列表中,d变化时e立刻变化*/ d=e |c; end 2,条件的描述完备性 如果if语句和case语句的条件描述不完备,也会造成不必要的锁存器。 Example1: if (a==1'b1) q=1'b1;//如果a==1'b0,q=?