Hi,

I wonder is there a decoder avalible for the following function? If not what is the simplest way to build one?



Input: 0 0 0 0 Output: 0 0 0.....................0
Input: 0 0 0 1 Output: 1 0 0.....................0
Input: 0 0 1 0 Output: 1 1 0.....................0
Input: 0 0 1 1 Output: 1 1 1.....................0


Input: 1 1 1 1 Output: 1 1 1.....................1


Thanks for help!

Regards,

Tom

 

No standard off the shelf logic chip would do that function. These days the simplest solution would be to program a microprocessor to perform this decoding, you would need to have enough I/O pins (20 in this case) but it would be a easily implemented.

 

A programmable logic device works well for this too. (Note, only 19 pins, 4-in and 15-out are needed)

Also, a standard decoder (for example 74159) could be combined with some or-gates.

Or, you can work out a solution with only gates.

 

Hi,

I wonder is there a decoder avalible for the following function? If not what is the simplest way to build one?



Input: 0 0 0 0 Output: 0 0 0.....................0
Input: 0 0 0 1 Output: 1 0 0.....................0
Input: 0 0 1 0 Output: 1 1 0.....................0
Input: 0 0 1 1 Output: 1 1 1.....................0


Input: 1 1 1 1 Output: 1 1 1.....................1


Thanks for help!

Regards,

Tom

You can make your own decoder using 16 four-input Nand gates and some inverters. If you have a TTL data book it will show you the 74154 design (four-input, 16-output) design, but you'd have to rewire it for your purpose. Good luck!