1. Logic Experiment 4
老師：伍紹勳
助教：江長庭
鄭仲傑

2. BCD Adder
Equipment：
IC：7408 x 1、7432 x 1、7483 x 2、7447(DCBA) x 1、LED x 1、7-Segment LED x 1

3. Review BCD number addition
Two units digit decimal number
ex: 7+8=15
BCD :
Determine whether to add 6 or not !!!!
>9 => add 6
Tens digit Units digit

4. F = T8T4 + T8T2 + K When to add 6? T8T4 + T8T2 Binary Sum BCD Sum
K T8 T4 T2 T1 C S8 S4 S2 S1 A B C D E F
When to add 6?
1. T8 T4 T2 T1 > 9 00 01
T8T4
T2T1
T8T4 + T8T2
2. Carry is 1
F = T8T4 + T8T2 + K

5. IC 7483 ( 4-bits full adder )

6. 7-Segment LED
Vcc a b c d e f g dp
Vcc

7. IC 7447

9. 務必加上電阻
A,K connect to +5V
dp not connect

10. 22 ohm

11. Requirement Two units digit decimal number addition in BCD
Input : two BCD number
Output : units digit – 7-Segment LED
tens digit – LED
Input不能大於9

12. Input
T8T4 + T8T2 + K
Add 6 or not
A,K connect to +5V
dp not connect
Units Digit
Tens Digit
( LED )