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Forum: FPGA, VHDL & Verilog Plz help it is not giving correct output it is showing in count 3'hX


von zahid i. (Company: UET) (zahidiqbal1990)


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module Up_Down(count, up_dwn, clock, reset_);
output [2:0] count;
input [1:0] up_dwn;
input clock, reset_;
reg [2:0] count;

reg [2:0] state, next_state;
parameter state_idle=3'b000, state_inc=3'b010, state_dec=3'b100;

always@ (posedge clock or posedge reset_ )
if(reset_) state<=state_idle;
else state<=next_state;

always @ (state or up_dwn)
begin next_state=state;
case(state)
state_idle:
begin
//if(up_dwn==2'b00 || up_dwn==2'b11)

if(up_dwn==2'b01)
begin
count<=count+1;
next_state=state_inc;
end
else if(up_dwn==2'b10)
begin
count<=count-1;
next_state=state_dec;
end
else
next_state= state_idle;
end


state_inc:
begin

if(up_dwn==2'b01)
begin
count<=count+1;
next_state=state_inc;
end
else if(up_dwn==2'b10)
begin
count<=count-1;
next_state=state_dec;
end
else
next_state= state_idle;

end

state_dec:
begin
if(up_dwn==2'b01)
begin
count<=count+1;
next_state=state_inc;
end
else if(up_dwn==2'b10)
begin
count<=count-1;
next_state=state_dec;
end
else
next_state= state_idle;
end
endcase
end

endmodule

von lkmiller (Guest)


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I'm a VHDL guy, but:
What about  initializing count with 0?

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