Copy of <F R I E N D>
See the difference between the two circuits . This one got less parts to give you a better understanding of this way of doing it. The others have sort of complete matrix for other letter sequences. This one got what it takes. Like in real life.
The binary code of the counter IC is transformed to decimal code by those 4 inverters and the 10 times three AND gates.
The OR gates encode them for the 7-segment display.
The connections of the OR gates is free of choice according to the letters or digits you want to program.
The 1st top left OR gate is the 'a' of the 7-segment display, the 7th the 'f'.
Understanding this enables you to write almost everything you want.
Enjoy
