create different clocks at Test Bench

Altera_Forum · ‎10-19-2013

Hi ,

i create 2 different clocks at Test Bench :

1. clk_25M - clk_period = 1/25 MHz = 40 nsec

1. clk_100M - clk_period = 1/100 MHz = 10 nsec

At Model Sim I see correct wave of clk_25M .

The wave of clk_100M is wrong , the wave start at '0' and after 45 nsec rise to '1' and after 45 nsec fall to '0' for 5 nsec and repeate .

why is that ?

Test Bench file and waves pictures attached .

Altera_Forum · ‎10-19-2013

thats because the 100 MHZ clock wont change until after the 25MHz clock has changed. You need to put the two clocks in separate processes.

Altera_Forum · ‎10-19-2013

Thanks , i learned new thing .