What would we do without them?
+---+--+---+ +---+---*---+ __ 1A |1 +--+ 20| VCC | A | B |/Y | /Y = AB 1B |2 19| 6B +===+===*===+ /1Y |3 18| 6A | 0 | 0 | 1 | 2A |4 17| /6Y | 0 | 1 | 1 | 2B |5 74 16| 5B | 1 | 0 | 1 | /2Y |6 804 15| 5A | 1 | 1 | 0 | 3A |7 14| /5Y +---+---*---+ 3B |8 13| 4B /3Y |9 12| 4A GND |10 11| /4Y +----------+
+---+--+---+ +---+---*---+ ___ 1A |1 +--+ 20| VCC | A | B |/Y | /Y = A+B 1B |2 19| 6B +===+===*===+ /1Y |3 18| 6A | 0 | 0 | 1 | 2A |4 17| /6Y | 0 | 1 | 0 | 2B |5 74 16| 5B | 1 | 0 | 0 | /2Y |6 805 15| 5A | 1 | 1 | 0 | 3A |7 14| /5Y +---+---*---+ 3B |8 13| 4B /3Y |9 12| 4A GND |10 11| /4Y +----------+
+---+--+---+ +---+---*---+ 1A |1 +--+ 20| VCC | A | B | Y | Y = AB 1B |2 19| 6B +===+===*===+ 1Y |3 18| 6A | 0 | 0 | 0 | 2A |4 17| 6Y | 0 | 1 | 0 | 2B |5 74 16| 5B | 1 | 0 | 0 | 2Y |6 808 15| 5A | 1 | 1 | 1 | 3A |7 14| 5Y +---+---*---+ 3B |8 13| 4B 3Y |9 12| 4A GND |10 11| 4Y +----------+
+---+--+---+ +---+---+---*---+ /OE |1 +--+ 24| VCC |/OE|CLK| D | Q | D1 |2 23| Q1 +===+===+===*===+ D2 |3 22| Q2 | 1 | X | X | Z | D3 |4 21| Q3 | 0 | / | 0 | 0 | D4 |5 20| Q4 | 0 | / | 1 | 1 | D5 |6 74 19| Q5 | 0 |!/ | X | - | D6 |7 821 18| Q6 +---+---+---*---+ D7 |8 17| Q7 D8 |9 16| Q8 D9 |10 15| Q9 D10 |11 14| Q10 GND |12 13| CLK +----------+
+---+--+---+ +---+---+---*---+ /OE |1 +--+ 24| VCC |/OE|CLK| D |/Q | D1 |2 23| /Q1 +===+===+===*===+ D2 |3 22| /Q2 | 1 | X | X | Z | D3 |4 21| /Q3 | 0 | / | 0 | 1 | D4 |5 20| /Q4 | 0 | / | 1 | 0 | D5 |6 74 19| /Q5 | 0 |!/ | X | - | D6 |7 822 18| /Q6 +---+---+---*---+ D7 |8 17| /Q7 D8 |9 16| /Q8 D9 |10 15| /Q9 D10 |11 14| /Q10 GND |12 13| CLK +----------+
+---+--+---+ /OE |1 +--+ 24| VCC D1 |2 23| Q1 D2 |3 22| Q2 D3 |4 21| Q3 D4 |5 20| Q4 D5 |6 74 19| Q5 D6 |7 823 18| Q6 D7 |8 17| Q7 D8 |9 16| Q8 D9 |10 15| Q9 /RST |11 14| /CLKEN GND |12 13| CLK +----------+
+---+--+---+ /OE1 |1 +--+ 24| VCC /OE2 |2 23| /OE3 D1 |3 22| Q1 D2 |4 21| Q2 D3 |5 20| Q3 D4 |6 74 19| Q4 D5 |7 825 18| Q5 D6 |8 17| Q6 D7 |9 16| Q7 D8 |10 15| Q8 /RST |11 14| /CLKEN GND |12 13| CLK +----------+
+---+--+---+ /OE1 |1 +--+ 24| VCC A1 |2 23| Y1 A2 |3 22| Y2 A3 |4 21| Y3 A4 |5 20| Y4 A5 |6 742 19| Y5 A6 |7 827 18| Y6 A7 |8 17| Y7 A8 |9 16| Y8 A9 |10 15| Y9 A10 |11 14| Y10 GND |12 13| /OE2 +----------+
+---+--+---+ +---+---*---+ 1A |1 +--+ 20| VCC | A | B | Y | Y = A+B 1B |2 19| 6B +===+===*===+ 1Y |3 18| 6A | 0 | 0 | 0 | 2A |4 17| 6Y | 0 | 1 | 1 | 2B |5 74 16| 5B | 1 | 0 | 1 | 2Y |6 832 15| 5A | 1 | 1 | 1 | 3A |7 14| 5Y +---+---*---+ 3B |8 13| 4B 3Y |9 12| 4A GND |10 11| 4Y +----------+
+---+--+---+ /OEA |1 +--+ 24| VCC A1 |2 23| B1 A2 |3 22| B2 A3 |4 21| B3 A4 |5 20| B4 A5 |6 74 19| B5 A6 |7 833 18| B6 A7 |8 17| B7 A8 |9 16| B8 /ERROR |10 15| PAR /CLR |11 14| /OEB GND |12 13| CLK +----------+
+---+--+---+ +---+---+---*---+ /OE |1 +--+ 24| VCC |/OE| LE| D | Q | D1 |2 23| Q1 +===+===+===*===+ D2 |3 22| Q2 | 1 | X | X | Z | D3 |4 21| Q3 | 0 | 0 | X | - | D4 |5 20| Q4 | 0 | 1 | 0 | 0 | D5 |6 74 19| Q5 | 0 | 1 | 1 | 1 | D6 |7 841 18| Q6 +---+---+---*---+ D7 |8 17| Q7 D8 |9 16| Q8 D9 |10 15| Q9 D10 |11 14| Q10 GND |12 13| LE +----------+
+---+--+---+ +----+----+---+---+---*---+ /OE |1 +--+ 24| VCC |/RST|/SET|/OE| LE| D | Q | D1 |2 23| Q1 +====+====+===+===+===*===+ D2 |3 22| Q2 | 0 | 1 | 0 | X | X | 0 | D3 |4 21| Q3 | 1 | 0 | 0 | X | X | 0 | D4 |5 20| Q4 | X | X | 1 | X | X | Z | D5 |6 74 19| Q5 | 1 | 1 | 0 | 0 | X | - | D6 |7 843 18| Q6 | 1 | 1 | 0 | 1 | 0 | 0 | D7 |8 17| Q7 | 1 | 1 | 0 | 1 | 1 | 1 | D8 |9 16| Q8 +----+----+---+---+---*---+ D9 |10 15| Q9 /RST |11 14| /SET GND |12 13| LE +----------+
+---+--+---+ /OE1 |1 +--+ 24| VCC /OE2 |2 23| /OE3 D1 |3 22| Q1 D2 |4 21| Q2 D3 |5 20| Q3 D4 |6 74 19| Q4 D5 |7 845 18| Q5 D6 |8 17| Q6 D7 |9 16| Q7 D8 |10 15| Q8 /RST |11 14| /SET GND |12 13| LE +----------+
+---+--+---+ S0 |1 +--+ 24| VCC 1A0 |2 23| S1 1A1 |3 22| 6A0 1Y |4 21| 6A1 2A0 |5 20| 6Y 2A1 |6 74 19| 5A0 2Y |7 857 18| 5A1 3A0 |8 17| 5Y 3A1 |9 16| 4A0 3Y |10 15| 4A1 ZD |11 14| 4Y GND |12 13| COMP +----------+
+---+--+---+ /GBA |1 +--+ 24| VCC A1 |2 23| B1 A2 |3 22| B2 A3 |4 21| B3 A4 |5 20| B4 A5 |6 74 19| B5 A6 |7 861 18| B6 A7 |8 17| B7 A8 |9 16| B8 A9 |10 15| B9 A10 |11 14| B10 GND |12 13| /GAB +----------+
+---+--+---+ /GBA1 |1 +--+ 24| VCC A1 |2 23| B1 A2 |3 22| B2 A3 |4 21| B3 A4 |5 20| B4 A5 |6 74 19| B5 A6 |7 863 18| B6 A7 |8 17| B7 A8 |9 16| B8 A9 |10 15| B9 /GBA2 |11 14| /GAB2 GND |12 13| /GAB1 +----------+
+---+--+---+ S0 |1 +--+ 24| VCC S1 |2 23| /ENP P0 |3 22| Q0 P1 |4 21| Q1 P2 |5 20| Q2 P3 |6 74 19| Q3 P4 |7 867 18| Q4 P5 |8 17| Q5 P6 |9 16| Q6 P7 |10 15| Q7 /ENT |11 14| CLK GND |12 13| /RCO +----------+
+---+--+---+ S0 |1 +--+ 24| VCC S1 |2 23| /ENP P0 |3 22| Q0 P1 |4 21| Q1 P2 |5 20| Q2 P3 |6 74 19| Q3 P4 |7 869 18| Q4 P5 |8 17| Q5 P6 |9 16| Q6 P7 |10 15| Q7 /ENT |11 14| CLK GND |12 13| /RCO +----------+
+---+--+---+ /1RST |1 +--+ 24| VCC /1OE |2 23| 1LE 1D1 |3 22| 1Q1 1D2 |4 21| 1Q2 1D3 |5 20| 1Q3 1D4 |6 74 19| 1Q4 2D1 |7 873 18| 2Q1 2D2 |8 17| 2Q2 2D3 |9 16| 2Q3 2D4 |10 15| 2Q4 /2OE |11 14| 2LE GND |12 13| /2RST +----------+
+---+--+---+ +----+---+---+---*---+ /1RST |1 +--+ 24| VCC |/RST|/OE|CLK| D | Q | /1OE |2 23| 1CLK +====+===+===+===*===+ 1D1 |3 22| 1Q1 | 0 | 1 | X | X | Z | 1D2 |4 21| 1Q2 | X | 0 | X | X | 0 | 1D3 |5 20| 1Q3 | 1 | 0 | / | 0 | 0 | 1D4 |6 74 19| 1Q4 | 1 | 0 | / | 1 | 1 | 2D1 |7 874 18| 2Q1 | 1 | 0 |!/ | X | - | 2D2 |8 17| 2Q2 +----+---+---+---*---+ 2D3 |9 16| 2Q3 2D4 |10 15| 2Q4 /2OE |11 14| 2CLK GND |12 13| /2RST +----------+
+---+--+---+ +----+---+---+---*---+ /1RST |1 +--+ 24| VCC |/RST|/OE|CLK| D | Q | /1OE |2 23| 1CLK +====+===+===+===*===+ 1D1 |3 22| 1Q1 | 0 | 1 | X | X | Z | 1D2 |4 21| 1Q2 | X | 0 | X | X | 0 | 1D3 |5 20| 1Q3 | 1 | 0 | / | 0 | 0 | 1D4 |6 74 19| 1Q4 | 1 | 0 | / | 1 | 1 | 2D1 |7 878 18| 2Q1 | 1 | 0 |!/ | X | - | 2D2 |8 17| 2Q2 +----+---+---+---*---+ 2D3 |9 16| 2Q3 2D4 |10 15| 2Q4 /2OE |11 14| 2CLK GND |12 13| /2RST +----------+
+---+--+---+ /B0 |1 +--+ 24| VCC /A0 |2 23| /A1 S3 |3 22| /B1 S2 |4 21| /A2 S1 |5 20| /B2 S0 |6 74 19| /A3 CIN |7 881 18| /B3 M |8 17| /G /F0 |9 16| COUT /F1 |10 15| /P /F2 |11 14| A=B GND |12 13| /F3 +----------+
+---+--+---+ L+/A |1 +--+ 24| VCC IA<B |2 23| ALE IA>B |3 22| A7 B7 |4 21| A6 B6 |5 20| A5 B5 |6 74 19| A4 B4 |7 885 18| A3 B3 |8 17| A2 B2 |9 16| A1 B1 |10 15| A0 B0 |11 14| OA<B GND |12 13| OA>B +----------+
+---+--+---+ O//E |1 +--+ 28| VCC /ERRA |2 27| /OEAB LEAB |3 26| B1 A1 |4 25| B2 A2 |5 24| B3 A3 |6 23| B4 A4 |7 74 22| B5 A5 |8 899 21| B6 A6 |9 20| B7 A7 |10 19| B8 A8 |11 18| BPAR APAR |12 17| LEBA /OEBA |13 16| /SEL GND |14 15| /ERRB +----------+