PoC.io.KeyPadScanner

This module drives a one-hot encoded column vector to read back a rows vector. By scanning column-by-column it’s possible to extract the current button state of the whole keypad. The scanner uses high-active logic. The keypad size and scan frequency can be configured. The outputed signal matrix is not debounced.

Entity Declaration:

 1  generic (
 2    CLOCK_FREQ              : FREQ        := 100 MHz;
 3    SCAN_FREQ               : FREQ        := 1 kHz;
 4    ROWS                    : positive    := 4;
 5    COLUMNS                 : positive    := 4;
 6    ADD_INPUT_SYNCHRONIZERS : boolean     := TRUE
 7  );
 8  port (
 9    Clock         : in  std_logic;
10    Reset         : in  std_logic;
11    -- Matrix interface
12    KeyPadMatrix  : out T_SLM(COLUMNS - 1 downto 0, ROWS - 1 downto 0);
13    -- KeyPad interface
14    ColumnVector  : out std_logic_vector(COLUMNS - 1 downto 0);
15    RowVector     : in  std_logic_vector(ROWS - 1 downto 0)
16  );
17end entity;