The heart of this project is the counter/display.
This module is based on CD4518 BCD counters. These really only count from 0 to 9, where each digit is represented with it's standard BCD nibble. The counter increments with rising edge of one input, or falling edge of the other (These are clock and enable pins). It's zeroed when at overflow or when the reset pin is pulled high. Each chip has 2 of these.
And really that's it. There's not much more to it. See for yourself in the datasheet.
But I wanted to use 7-segment LED display. I must convert the 4-bit bcd somehow. I decided to use a converter chip, named CD4511. It's no more than combinatorial logic with a latched inputs. See for yourself too.
I want to prove that I can count from 0 to 9 (you can call it counting to 10) and display it on a 7 segment display.
So I built a basic circuit which consists of one CD4060 (to generate a clock), one CD4518 which counts to 10 and one CD4511 to light a 7-segment display accordingly.
The thing has worked very nicely - I can count to 10 :)