## On the Subject of Boolean Keypads

Whoever designs these modules must really like Boolean logic.

IF AND ONLY IF a button’s operation results in a True value shall the button be pressed.

Buttons must be pressed IN READING ORDER.

### Operations

Buttons can have one of the following boolean operations:

- AND
- OR
- XOR
- NAND
- NOR
- XNOR

The operation is determined by the symbol on the button. Please refer to the table on the following page.

### Evaluating the Operation

- Find out the input values of the button. This is done by looking at the LEDs above and to the right of the button: ON = True, OFF = False
- Find out the operation on the button by referring to the table above.
- Evaluate the operation with the given inputs. In case you don’t know how and don’t wanna blow up, refer to the last section.

#### Logic Gate Identification Reference

- An AND gate returns TRUE only if both inputs are TRUE.
- An OR gate returns TRUE if at least one input is TRUE.
- An XOR gate returns TRUE if exactly one input is TRUE.
- A NAND gate returns FALSE if both inputs are TRUE. Otherwise, it returns TRUE.
- A NOR gate returns FALSE if at least one input is TRUE. Otherwise, it returns TRUE.
- An XNOR gate returns TRUE if both inputs are equal.