We are going to use a hardware counter with 555 to count numbers continuously. 555 will give out clocks to motivate the counter.

We need to draw a random number out and then draw another random number. this action is controlled by software.

Our question is that:
1) after drew a random number (let say the number is 1), and then draw the second number (let say the number is 10)..

after that, we repeat 1) again and the number let say is 11, and the second number is 21... that means the clock is too short to draw... and the difference between the two numbers are the same.. it's not our ideal plan. we want to draw any numbers will different distance between every drawing!

so what can we do to change the distance by software?

Thank you!