I need to create a pseudo code / sequential circuit design for a counter that displays digits "9" to "0" in a 7-segment LCD display. Each digit display duration is supposed to last for about 5 - 8 seconds each. Taking note that a 555 timer cannot be used directly. My problem is that I don't know how to do this in way that is efficient and conventional. Can someone tell me a simple way to do so?

 

Note that it was instructed that we can only make use of simple flip flops (D, T, JK) and combinational circuits (Decoder, Multiplexer etc.)

 

Don't worry too much about "conventional" and "efficient" at first -- get something that works, no matter how ugly.

What are you allowed to use for a clock?

That aside, assume you have a clock at a suitable frequency. How many flip flops do you need?

Have you put together a state table?