quan
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Hi all, I am a student and I am working on a homework. Shortly, I will summary shortly the hw's requirement. It said some thing like that: At first, when counter goes from 0->7 then led 1 on; when the counter up to 8 then led 2 on, up to 9 then led 3 on. Next, when the counter comes to 10, it depends on a switch, if switch is on, led 4 on, if switch is off led 5 on. And if led 4 on, it still to be on until counter comes to 14 then counter reset to 0 and comes back to first stage which means led 1 on. And similarly, if led 5 on, it still to be on until counter comes to 22 then counter reset to 0 and comes back to first stage which means led 1. The requirement is described by a lots of word but shortly it will be like that after I design FSM for the problem. When I finish my code, test bench runs OK but when I run on Altera DE1 board, it did not run like my expectation. When the counter comes to 8,9,10 it runs nicely but next when led 4 or led 5 on, it immediately comes back to stage 1 (led 1 on). Led 4 should be on 4 seconds or led 5 should be on 12 seconds before come back to stage 1. In test bench, it waiting but in the board nothing is waiting. This is my code, hope you guys help me.
module controller(sw, clk, rst, led, y, Y); //This is top level module input sw, clk, rst; output [4:0] led; output reg [2:0]y=0,Y=0; //y: present state; Y: next state parameter [2:0] fer=0, ready=1, prepare=2, transfer=3, flush=4; //define finite state machine reg [4:0] count=0; //counter frequency_divider C1(clk, clk_out); //divider frequency for DE1 board, I use pin L1 (50Mhz) always@(count, sw,y) case(y) fer: if (count==8) Y=ready; ready: if (count==9) Y=prepare; prepare: if ((count==10) & (sw==0)) Y=flush; else if ((count==10) & (sw==1)) Y=transfer; transfer: if (count==14) Y=fer; flush: if ( count==22) Y=fer; default: Y=2'bxx; endcase
endcase
always @(negedge rst, posedge clk_out) if (!rst) y<=fer; else y<=Y; always @(negedge rst, posedge clk_out) if (!rst) count = 0; else begin count = count + 1; if (y==transfer && count==15) //This to reset the counter count=0; else if (y==flush && count==23) count=0; end assign led[0]=(y==fer); // led 0 on when the system in fermertation stage (stage 1) assign led[1]=(y==ready); assign led[2]=(y==prepare); assign led[3]=(y==transfer); assign led[4]=(y==flush); endmodule module frequency_divider(clk_in, clk_out); input clk_in; output clk_out; reg [31:0] num=0; wire clk_out=num[24]; always @(posedge clk_in) begin num <= num+ 1; end endmodule
module test_controller; //test bench wire [4:0]led; reg sw, clk, rst; controller C1(sw, clk, rst, led);
initial begin sw=0; clk=0; rst=0; #2rst=1; end
always begin #1 clk=~clk; end always begin #100 sw=~sw; end
endmodule
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