anchor.diff:  
   groups() -> [digital, input].
   
  -version() -> "0.1.0". 
  +version() -> "0.2.0". 
   
   
   %% Merge the block type specific, Config, Input, and Output attributes
  
positive.code:     block_common:configs(BlockName, ?MODULE, version(), Description), 
      [
        {gpio_pin, {0}}, %| int | 0 | 0..40 |
        {invert_output, {false}} %| bool | false | true, false |
      ]). 
                              
  
negative.code: 
  initialize({Config, Inputs, Outputs, Private}) ->
  
    {ok, InterruptEdge} = attrib_utils:get_value(Config, interrupt_edge),
  
    case config_utils:init_gpio(Config, gpio_pin, input) of
      {ok, GpioPinRef} ->
        Private1 = attrib_utils:add_attribute(Private, {gpio_pin_ref, {GpioPinRef}}),
        Status = initialed,
        Value = null,
        gpio_utils:set_int(GpioPinRef, InterruptEdge);
  
      {error, _Reason} ->
        Value = null, Status = proc_err,
  