Logic Experiment 4
老師:伍紹勳助教:江長庭 鄭仲傑
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
Review BCD number addition
• Two units digit decimal number
ex: 7+8=15
BCD :
0 1 1 1
+1 0 0 0
1 1 1 1
+0 1 1 0
0 0 0 1 0 1 0 1
Determine whether to add 6 or not !!!!
>9 => add 6
Tens digit Units digit
Binary Sum BCD Sum K T8 T4 T2 T1 C S8 S4 S2 S1
0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1 1 2 0 0 0 1 0 0 0 0 1 0 2 3 0 0 0 1 1 0 0 0 1 1 3 4 0 0 1 0 0 0 0 1 0 0 4 5 0 0 1 0 1 0 0 1 0 1 5 6 0 0 1 1 0 0 0 1 1 0 6 7 0 0 1 1 1 0 0 1 1 1 7 8 0 1 0 0 0 0 1 0 0 0 8 9 0 1 0 0 1 0 1 0 0 1 9 A 0 1 0 1 0 1 0 0 0 0 10 B 0 1 0 1 1 1 0 0 0 1 11 C 0 1 1 0 0 1 0 0 1 0 12 D 0 1 1 0 1 1 0 0 1 1 13 E 0 1 1 1 0 1 0 1 0 0 14 F 0 1 1 1 1 1 0 1 0 1 1510 1 0 0 0 0 1 0 1 1 0 1611 1 0 0 0 1 1 0 1 1 1 1712 1 0 0 1 0 1 1 0 0 0 1813 1 0 0 1 1 1 1 0 0 1 19
When to add 6?
1. T8 T4 T2 T1 > 9
00 01 11 10
00
01
11 1 1 1 1
10 1 1
T8T4
T2T1
T8T4 + T8T2
2. Carry is 1
F = T8T4 + T8T2 + K
IC 7483 ( 4-bits full adder )
7-Segment LED
ab
cd
e
fg
dp
Vcc
Vcc
IC 7447
A,K connect to +5Vdp not connect
務必加上電阻
22 ohm
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
T8T4 + T8T2 + K
Tens Digit ( LED )
Units Digit
Add 6 or not
A,K connect to +5Vdp not connect
Input