counters

I need to have a 2-digit down counter based on read-only memory RAM or ROM and to show the count on a 7-segment display, all done in Logisim or in another program. Can someone help me thanks

I need to design an Automated system such that a user gives inputs in 3 bits and there's a clock running that resets itself and gives a positive signal after the time indicated by input. We can use logic gates, combinatorial circuits, sequential circuits, counters, registers.