random adder(counter) error in FSM

[JUNIOR]

Hi,

I have random adder error in FSM problem

the current result of reg [15:0]counter is : 1,2,3,4,5,4,5,6

but the correct result would be 1,2,3,4,5,6,7,8

Does anyone know how to fix this, any reply is appreciated.

always@(negedge CLOCK_50)

begin  

  case(CS)

   S0:

   begin

    if(GPIO_1[9]==1'b0)

    begin

    counter=counter+1;

    CS=S1;

    end

    else

    begin

    CS=S0;

    end

   end

   S1:

   begin

    if(GPIO_1[9]==1'b1)

    begin

    CS=S0;

    end

    else

    begin

    CS=S1;

    end

   end

   endcase

end

[sstrell]

I think you have to look at the toggling of GPIO_1[9] since that seems to be what's required to continue the count.

#iwork4intel

[JUNIOR]

​Thanks and I solve it by add one flip-flop to eliminate the glitch, replace GPIO with synchronized register

always@(negedge CLOCK_50)

begin

REG_GPIO_1_9<= GPIO_1[9];

end