Programming instructions

TTL
Multisim Component Reference Guide 6-44 ni.com
6.4.79 74xx247 (BCD-to-seven segment dec)
The BCD -to-seven-segment decoder/driver features active-low outputs designed for driving
indicators directly. It has full ripple-blanking input/output controls and a lamp test input.
BCD-to-seven-segment decoder/driver truth table:
Notes:
1. The blanking input (BI) must be open or held at a high logic level when output
functions 0 through 15 are desired. The ripple-blanking input (RBI
) must be open or
high if blanking of a decimal zero is not desired.
2. When a low logic level is applied to the blanking input (BI), all segment outputs are
off regardless of any other input.
3. When ripple-blanking input (RBI) and inputs A, B, C, and D are at a low level with
the lamp test input high, all segment outputs go off and the ripple-blanking output
(RBO) goes to a low level (response condition).
4. When the blanking input/ripple-blanking output (BI/RBO) is open or held high and a
low is applied to the lamp-test input, all segment outputs are on.
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