anchor.diff:     method Action sfp(Bit#(1) refclk);
      method Bit#(4) serial_tx_data;
      method Action serial_rx(Bit#(4) data);
  -   method Bit#(1) led0;
  -   method Bit#(1) led1;
  -   method Bit#(1) led2;
  -   method Bit#(1) led3;
  +   method Bit#(4) led;
      method Bit#(4) led_bracket;
      method Action buttons(Vector#(4, Bit#(1)) v);
      interface Si570wrapI2c i2c;
  
positive.code:       led3.setPeriod(led_off, 500, led_on_max, 500);
     endrule
  
     method led0_out = led0.ifc.out;
     method led1_out = led1.ifc.out;
     method led2_out = led2.ifc.out;
     method led3_out = led3.ifc.out;
  endmodule
  
  interface De5SfpCtrl#(numeric type nPorts);
  
negative.code: endmodule
  
  interface De5Leds;
     method Bit#(4) led_out;
  endinterface
  
  module mkDe5Leds#(Clock clk0, Clock clk1, Clock clk2, Clock clk3)(De5Leds);
  