On the Subject of Boolean Keypads

Whoever designs these modules must really like Boolean logic.

IF AND ONLY IF a buttons 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 following table:

Symbol Table

AND OR XOR NAND NOR XNOR
ʯʭΛϮωЪ
ӇƸΦЬΞϚ
ԊȜɊǮۍ
ҌیԒҼӼӶ
ԬՊ֍ד۞ٻ
ۺϽ֎Խ

Evaluating the Operation

  1. 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
  2. Find out the operation on the button by refering to the table above.
  3. 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.