Idea was inspired by Ben Eater
The main idea of this project is to have 4 inputs which you can operate to display input-related numbers in HEX on a 7-segment display
Down below you can see a truthtable I made for this project and an image of a 7-segment display with a letter on every diode:
| Input 1 | Input 2 | Input 3 | Input 4 | a | b | c | d | e | f | g | num | HEX | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 0 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 0 | |
| 0 | 0 | 0 | 1 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 1 | 1 | |
| 0 | 0 | 1 | 0 | 1 | 1 | 0 | 1 | 1 | 0 | 1 | 2 | 2 | |
| 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 1 | 3 | 3 | |
| 0 | 1 | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 1 | 1 | 4 | 4 | |
| 0 | 1 | 0 | 1 | 1 | 0 | 1 | 1 | 0 | 1 | 1 | 5 | 5 | |
| 0 | 1 | 1 | 0 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 6 | 6 | |
| 0 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 7 | 7 | |
| 1 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 8 | 8 | |
| 1 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 9 | 9 | |
| 1 | 0 | 1 | 0 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 10 | A | |
| 1 | 0 | 1 | 1 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 11 | b | |
| 1 | 1 | 0 | 0 | 1 | 0 | 0 | 1 | 1 | 1 | 0 | 12 | C | |
| 1 | 1 | 0 | 1 | 0 | 1 | 1 | 1 | 1 | 0 | 1 | 13 | d | |
| 1 | 1 | 1 | 0 | 1 | 0 | 0 | 1 | 1 | 1 | 1 | 14 | E | |
| 1 | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 1 | 1 | 1 | 15 | F |
Firstly I had to make an equation for every output and simplify it, so I can build a logical circuit out of it.
I had two choices on how to make it:
In the common cathode display, all the cathode connections of the LED segments are connected together to ‘logic 0’ / GND. The individual > segments are then illuminated by applying HIGH / ’logic 1’ signal to the individual Anode terminals (a-g).
OR
In the common anode display, all the anode connections of the LED segments are joined together to logic “1”. The individual segments are illuminated by applying a ground, logic “0” or “LOW” signal to the Cathode of the particular segment (a-g).
This explanation is taken from this Website
So I planned to use the common anode way, because the truth table has less zero's than one's.
IN THIS CASE NOT CHANGING THE TRUTH TABLE MEANS THAT ON THE LOGIC CIRCUIT THE INPUT PATTERN WILL GIVE THE OPPOSITE OUTPUT (F.E. 0001 WILL GIVE 1)
- All the following Logic circuits can be found here in Logism Format
- a = Input 1, b = Input 2, c = Input 3, d = Input 4
