module top_module (
input clk,
input reset,
output [9:0] q
);
always @(posedge clk) begin
if (reset) begin
q <= 'd0;
end
else if (q=='d999) begin
q <= 'd0;
end
else begin
q <= q + 'd1;
end
end
endmodule
2.Exams/review2015 shiftcount
bash复制代码
module top_module (
input clk,
input shift_ena,
input count_ena,
input data,
output [3:0] q
);
always @(posedge clk) begin
if (shift_ena) begin
q <= {q[2:0],data};
end
else if (count_ena) begin
q <= q - 'd1;
end
else begin
q <= q;
end
end
endmodule
3.Exams/review2015 fsmseq
bash复制代码
module top_module (
input clk,
input reset, // Synchronous reset
input data,
output start_shifting);
reg[2:0] state, next_state;
parameter start=0,one=1,two=2,three=3,four=4;
always@(posedge clk) begin
if(reset)
state<=start;
else
state<=next_state;
end
always@(*) begin
case(state)
start:
begin
if(data)
next_state<=one;
else
next_state<=start;
end
one:
begin
if(data)
next_state<=two;
else
next_state<=start;
end
two:
begin
if(data)
next_state<=two;
else
next_state<=three;
end
three:
begin
if(data)
next_state<=four;
else
next_state<=start;
end
four:
begin
next_state<=four;
end
endcase
end
assign start_shifting=(state==four);
endmodule
4.exams/review2015_fsmshift
bash复制代码
module top_module (
input clk,
input reset, // Synchronous reset
output shift_ena);
reg[1:0] count;
always@(posedge clk) begin
if(reset)
count<=0;
else
count<=count+1;
end
always@(posedge clk) begin
if(reset)
shift_ena<=1;
else
if(count==3)
shift_ena<=0;
else
shift_ena<=shift_ena;
end
endmodule
5.Exams/review2015 fsm
bash复制代码
module top_module (
input clk,
input reset, // Synchronous reset
input data,
output shift_ena,
output counting,
input done_counting,
output done,
input ack );
parameter s=0,
s1=1,
s11=2,
s110=3,
b0=4,
b1=5,
b2=6,
b3=7,
count=8,
wait1=9;
reg[3:0] state,next_state;
always@(posedge clk) begin
if(reset)
state<=s;
else
state<=next_state;
end
always@(*) begin
case(state)
s:
begin
if(data)
next_state<=s1;
else
next_state<=s;
end
s1:
begin
if(data)
next_state<=s11;
else
next_state<=s;
end
s11:
begin
if(data)
next_state<=s11;
else
next_state<=s110;
end
s110:
begin
if(data)
next_state<=b0;
else
next_state<=s;
end
b0:
begin
next_state<=b1;
end
b1:
begin
next_state<=b2;
end
b2:
begin
next_state<=b3;
end
b3:
begin
next_state<=count;
end
count:
begin
if(done_counting)
next_state<=wait1;
else
next_state<=count;
end
wait1:
begin
if(ack)
next_state<=s;
else
next_state<=wait1;
end
endcase
end
assign shift_ena=((state==b0)||(state==b1)||(state==b2)||(state==b3));
assign counting=(state==count);
assign done=(state==wait1);
endmodule
6.Exams/review2015 fancytimer
bash复制代码
module top_module (
input clk,
input reset, // Synchronous reset
input data,
output [3:0] count,
output counting,
output done,
input ack );
parameter s=4'd0,s1=4'd1,s11=4'd2,s110=4'd3,b0=4'd4,b1=4'd5,b2=4'd6,b3=4'd7,Count=4'd8,WAIT=4'd9;
reg [3:0] state,next_state;
reg [3:0] temp_in;
reg [15:0] counter;
reg [3:0] a;
wire done_counting;
always @(posedge clk)
begin
if(reset)
state <= s;
else
state <= next_state;
end
always @(posedge clk)
begin
if(reset)
counter <= 16'd0;
else if(next_state == WAIT)
counter <= 16'd0;
else if(next_state == Count)
counter <= counter + 1'b1;
end
always @(*)
begin
if(counter <= 16'd1000)
a = 4'd0;
else if(counter <= 16'd2000)
a = 4'd1;
else if(counter <= 16'd3000)
a = 4'd2;
else if(counter <= 16'd4000)
a = 4'd3;
else if(counter <= 16'd5000)
a = 4'd4;
else if(counter <= 16'd6000)
a = 4'd5;
else if(counter <= 16'd7000)
a = 4'd6;
else if(counter <= 16'd8000)
a = 4'd7;
else if(counter <= 16'd9000)
a = 4'd8;
else if(counter <= 16'd10000)
a = 4'd9;
else if(counter <= 16'd11000)
a = 4'd10;
else if(counter <= 16'd12000)
a = 4'd11;
else if(counter <= 16'd13000)
a = 4'd12;
else if(counter <= 16'd14000)
a = 4'd13;
else if(counter <= 16'd15000)
a = 4'd14;
else
a = 4'd15;
end
assign done_counting = ((state == Count)&(counter == (temp_in + 1)*1000))?1'b1:1'b0;
always @(*)
begin
case(state)
s:next_state = data?s1:s;
s1:next_state = data?s11:s;
s11:next_state = data?s11:s110;
s110:next_state = data?b0:s;
b0:begin next_state = b1;temp_in[3] = data; end
b1:begin next_state = b2;temp_in[2] = data; end
b2:begin next_state = b3;temp_in[1] = data; end
b3:begin next_state = Count;temp_in[0] = data; end
Count:next_state = done_counting?WAIT:Count;
WAIT:next_state = ack?s:WAIT;
endcase
end
assign count = (state == Count)?(temp_in - a):4'd0;
assign counting = (state == Count);
assign done = (state == WAIT);
endmodule
