blinkin it the right way

test.sv

module REG (CLK, WE, D, O);

  parameter BITWIDTH = 1;
  parameter [BITWIDTH-1:0] INIT = '0;

  input CLK;
  input WE;
  input [BITWIDTH-1:0] D;
  output [BITWIDTH-1:0] O;

  genvar i;
  generate for (i = 0; i < BITWIDTH; i = i + 1) begin : loop
    // gowin's def of Sync WE FF primitive
    DFFE _b (.CLK(CLK), .D(D[i]), .CE(WE), .Q(O[i]));
    defparam _b.INIT = INIT[i];
  end endgenerate
endmodule

module led2 (
    input sys_clk,          // clk input
    output logic [5:0] led    // 6 LEDS pin
);

  parameter DELAY = 24'd1349_9999;
  typedef logic [6-1:0] LEDS;
  typedef logic [24-1:0] COUNTER;

  bit counter_wen ;
  COUNTER counter_in ;
  COUNTER counter_out ;
  REG _counter (.CLK(sys_clk), .WE(counter_wen), .D(counter_in), .O(counter_out)) ;
  defparam _counter.BITWIDTH = 24;
  
  bit leds_wen ;
  LEDS leds_in ;
  LEDS leds_out ;
  REG _leds (.CLK(sys_clk), .WE(leds_wen), .D(leds_in), .O(leds_out));
  defparam _leds.BITWIDTH = 6;

  always_comb begin
    // Default assignments
    led = ~leds_out; 
    counter_wen = 1'b1;  // Always enable the counter write
    counter_in = counter_out + 24'd1;  // Increment counter by default
    leds_wen = 1'b0;  // Disable LED write by default
    leds_in = 'z;  // High-impedance by default

    // Special case when counter reaches DELAY
    if (counter_out == DELAY) begin
        counter_in = 24'd0;  // Reset the counter
        leds_wen = 1'b1;  // Enable LED write
        leds_in = leds_out + 1'b1;  // Increment the LEDs
    end
  end

endmodule