74148: 8-Bit Priority Encoder

This is a specialized TTL device. It lets you rank eight inputs in order of importance. It produces as an output a binary word indicating the most important input present at any given time.

Selected inputs are placed on the 1-2-3-4-5-6-7 input lines. At the 1, 2, 4 outputs, the binary equivalent of the most significant (largest) input line selected will appear.

The Enable input must be low to get an output.

The ES output will go low if any input (one or more) is selected. The GS output will go high if any input (one or more) is selected and the Enable input is low.

The package may also be used as a keyboard encoder or as an 8-line-to-3-line encoder. It is expandable. Consult data sheet for more information.

Pinout
Pin # Pin Assignment
1 Input 4
2 Input 5
3 Input 6
4 Input 7
5 Enable
6 Output 4
7 Output 2
8 Ground
9 Output 1
10 Input 0
11 Input 1
12 Input 2
13 Input 3
14 GS
15 ES
16 Power (+5V)

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