Hello, I am designing a project in which I need to register the input from a 4x4 matrix KeyPad (this model) and to do so I have written the following VHDL test code:
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
entity Display is
Port (
selected : in std_logic;
Row_Vector : in std_logic_vector(3 downto 0);
Col_Vector : in std_logic_vector(3 downto 0);
display_code : out std_logic_vector(6 downto 0);
display_ctrl : out std_logic_vector(3 downto 0)
);
end Display;
architecture Behavioral of Display is
signal Displayed : std_logic_vector(3 downto 0);
begin
process(Displayed)
begin
case Displayed is
when "0000" => display_code <= "0000001"; -- "0"
when "0001" => display_code <= "1001111"; -- "1"
when "0010" => display_code <= "0010010"; -- "2"
when "0011" => display_code <= "0000110"; -- "3"
when "0100" => display_code <= "1001100"; -- "4"
when "0101" => display_code <= "0100100"; -- "5"
when "0110" => display_code <= "0100000"; -- "6"
when "0111" => display_code <= "0001111"; -- "7"
when "1000" => display_code <= "0000000"; -- "8"
when "1001" => display_code <= "0000100"; -- "9"
when "1010" => display_code <= "0000010"; -- a
when "1011" => display_code <= "1100000"; -- b
when "1100" => display_code <= "0110001"; -- C
when "1101" => display_code <= "1000010"; -- d
when "1110" => display_code <= "0110000"; -- E
when "1111" => display_code <= "0111000"; -- F
when others => display_code <= "1111111";
end case;
end process;
process(selected,Row_Vector,Col_Vector)
begin
if selected = '0' then
Displayed <= Row_Vector;
else
Displayed <= Col_Vector;
end if;
end process;
display_ctrl <= "1110";
end Behavioral;
I have attached all the source code for my test, which includes a button debouncer (U18 button), which I push to show the value that I read from the A14,A16,B15 and B16 pins for the rows and A15,A17,C15 and C16 for the columns of the KeyPad.
For example: when there are no cables connected to the row pins and I have not pushed the button, the value read from the row pins is shown in the 7-Segment display, which is "1111" (F). This means that when I connect a cable on any of the pins, a '0' is written at the input pin. If I connect a cable at the first row pin, the value read is "1110" and E is displayed. Following this logic, when I connect a cable to the second row pin and I leave the other ones disconnected, it should be displayed D ("1101") but instead 8 is displayed, which corresponds to "1000", which would mean that I have row 1, row 2 and row 3 cables connected, which is not the case.
What could be the problem here? My main problem is to undestand how to communicate the keypad with the Basys3 FPGA
Test_Code.zip
