Programming instructions

74xx
 National Instruments Corporation 6-41 Multisim Component Reference Guide
6.4.72 74xx22 (Dual 4-In NAND (OC))
This device contains two independent 4-input NAND gates. For correct performance, the
open collector outputs require pull-up resistors.
Logic function:
NAND gate truth table:
6.4.73 74xx238 (3-to-8 line Dec/DEMUX)
The logic levels at the C B and A inputs select one of the eight lines. G1 is an active-high
enable input while G2A and G2B are active-low enable inputs.
3-to-8 decoder/demultiplexer truth table:
Y = ABCD
ABCDY
11110
0XXX1
X0XX1
XX0X1
XXX01
SELECT OUTPUTS
G1 G2A
G2B CBAY0Y1Y2Y3Y4Y5Y6Y7
X1XXXX00000000
XX1XXX00000000
0XXXXX00000000
10000010000000
10000101000000
10001000100000
10001100010000
10010000001000
10010100000100
10011000000010
10011100000001
ComponentRef.book Page 41 Thursday, December 7, 2006 10:12 AM