ASYD/ASYD_Safety/Ada_Microbit/examples/MicroBit/buttons/README.md

Buttons Example

In this example we will see how to use the two buttons of the micro:bit.

Code

To know if a button is pressed or not, we will use the function State of the MicroBit.Buttons package.

   type Button_State is (Pressed, Released);

   type Button_Id is (Button_A, Button_B);

   function State (Button : Button_Id) return Button_State;

Arguments:

• Button : The Id of the button that we want to check. There are two Ids: Button_A or Button_B.

Return value:

The function State return the Button_State that can be either Pressed or Released.

Here is the code:

with MicroBit.Display;
with MicroBit.Buttons; use MicroBit.Buttons;
with MicroBit.Time;

procedure Main is
begin

   loop
      MicroBit.Display.Clear;

      if MicroBit.Buttons.State (Button_A) = Pressed then
         --  If button A is pressed

         --  Display the letter A
         MicroBit.Display.Display ('A');

      elsif MicroBit.Buttons.State (Button_B) = Pressed then
         --  If button B is pressed

         --  Display the letter B
         MicroBit.Display.Display ('B');
      end if;

      MicroBit.Time.Delay_Ms (200);
   end loop;
end Main;