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1. Programmable Keyboard/Display Interface THE 8279

2. Block diagram of 8279 based system 8085 8279 16-character Display 16-Key Matrix Keyboard Keyboard Control Decoder SL0 SL1 SL2 SL3 BD A3-A0 B3-B0 RL3-RL0 D7-D0 RD WR IRQ CLK A0

6. Block Diagram 8279 Keyboard Section

8. Block Diagram 8279 Display Section

10. Block Diagram 8279 Scan Section

12. Block Diagram 8279 MPU Interface Section

15. Scanning keys of a Matrix Keyboard Vcc Row0 Row1 Row2 Row3 C0 C1 C2 C3 R = 4.7K R = 4.7K 0 1 2 3 4 5 6 7 8 9 A B C D E F

16. Connecting a 7-segment display with 8279 8279 4-to-16 decoder SL0 SL1 SL2 SL3 A0 A1 A2 A3 B0 B1 B2 B3 a b c d e f g h O 15 O 0 V CC a b c d e f g h V CC O 1

17. Working with a multiplexed display 8279 4-to-16 decoder SL0 SL1 SL2 SL3 A0 A1 A2 A3 B0 B1 B2 B3 O 15 O 0 T1 O 1 T2 O 2 T3 O 3 T4

18. Connecting a 64-key Keyboard with 8279 8279 4-to-16 decoder SL0 SL1 SL2 SL3 RL0 O 13 O 0 O 7 Multiplexed 7-Segment Display O 8 O 9 O 10 O 11 O 12 O 14 O 15 RL1 RL2 RL3 RL4 RL5 RL6 RL7