divider by a fractional value

[Charlie.za]

fractional value

Hi, this is my problem (it's the continue of the topic:"frequency divider with NCO"):

I've to describe a clock frequency divider by a fractional value. All digital in VHDL (also behavioral). What can I do ?

Thanks for your advices

Charlie

 

[Al Farouk]

use what is called ratio counter, its function as follows
1- decide the ratio you want to divide your clock by say it is P/N
2- use a modulo N counter that each step in increas by P (accumulation of P) and and when its value increase N divid by N and keep the remainder in the counter and continue increas by P. and so on
3- each time the value in the accumulator increase N toggel your output.
4- you will get output frequency equal F * P/N. where P/N is the required ratio.