7 Segment to BCD encoder

7seg2bcd.mjs

const seg7_bcd = ([a, b, c, d, e, f, g]) => {
  const w = (a & b & f & g) | (!b & !c & e) | (!a & e);
  const x = (!a & b & g) | (a & !f & !g) | (a & !b);
  const y = (!b & e & g) | (!d & e) | (a & !f);
  const z = (!c & !d & g) | (c & !f) | (a & !e) | (!a & e);
  return [w, x, y, z];
};

const TRUTH_TABLE = [
  ["0000000", "0000", " "],
  ["1111110", "0000", "0"],
  ["0110000", "0001", "1"],
  ["1101101", "0010", "2"],
  ["1111001", "0011", "3"],
  ["0110011", "0100", "4"],
  ["1011011", "0101", "5"],
  ["1011111", "0110", "6"],
  ["1110000", "0111", "7"],
  ["1111111", "1000", "8"],
  ["1110011", "1001", "9"],
  ["1110111", "1010", "A"],
  ["0011111", "1011", "b"],
  ["1001110", "1100", "C"],
  ["0111101", "1101", "d"],
  ["1001111", "1110", "E"],
  ["1000111", "1111", "F"],
]
  .map(([i, o, l]) => [i, o, l])
  .map(([[a, b, c, d, e, f, g], [w, x, y, z], l]) => [
    ...[a, b, c, d, e, f, g, w, x, y, z].map(Number),
    l,
  ])
  .map(([a, b, c, d, e, f, g, w, x, y, z, l]) => ({
    i: { a, b, c, d, e, f, g },
    o: { w, x, y, z },
    l,
  }));

for (const { i, o, l } of TRUTH_TABLE) {
  const result = seg7_bcd(Object.values(i));

  const comparison = result.every((v, i) => v === o[["w", "x", "y", "z"][i]]);

  console.log(
    `${comparison ? "✅" : "❌"} Letter ${l}: Input ${Object.values(
      i
    )} expected ${Object.values(o)} got ${result}`
  );
}

7seg2bcd.vhdl

LIBRARY ieee;
USE ieee.std_logic_1164.all;

ENTITY n7seg_bcd IS
  PORT (
    A, B, C, D, E, F, G : IN STD_LOGIC;
    W, X, Y, Z : OUT STD_LOGIC
  );
END n7seg_bcd;

ARCHITECTURE Behavioral OF n7seg_bcd IS
BEGIN
  PROCESS (A, B, C, D, E, F, G)
  BEGIN
    
    -- W is set for letterss 1, 3, 5, 7, 9, B, D, F
    W <= A and B and F and G or
         not(B) and not(C) and E or
         not(A) and E;
  
    -- X is set for letters 2, 3, 6, 7, A, B, E, F 
    X <= not(A) and B and G or
         A and not(F) and not(G) or
         A and not(B);

    -- Y is set for letters 4, 5, 6, 7, C, D, E, F
    Y <= not(B) and E and G or
         not(D) and E or
         A and not(F);

    -- Z is set for letters 8, 9, A, B, C, D, E, F
    Z <= C and not(F) or
         not(C) and not(D) and not(G) or
         A and not(E) or
         not(A) and E or
         A and not(E);

  END PROCESS;
END Behavioral;

README.md