How to generate the 30s delay, traffic light, vhdl code

[alle]

Any ways that I can generate a 30s delay for my traffic light vhdl code? the red light will stay for 30s, yellow light for 2s. How to generate these delay? Pls help.

 

[Mr.LB]

How to generate delay?

DESIGN A COUNTER AND BE CAREFUL WITH YOU SYSTEM CLOCK FOR EXAMPLE YOU HAVE A CLOCK FO 40M ,25ns FOR ONE CYCLE.YOU WILL DESIGN A COUNTER OF (30S+2S)/25NS

IT ISN'T VERY DIFFICULT,IS IT?

 

[alle]

Re: How to generate delay?

perhaps not for you but it is for me.. since im just starting to adapt to vhdl couple of days ago.. thats why i need some directions

 

[shahidE636]

Re: How to generate delay?

Use Wait statements with time.

example is :


Wait for 100ns;


where ns is for nano-sec. you can mili-sec (ms) or only sec (s)

 

[devas]

Re: How to generate delay?

Wait statements are not synthesizable.

You need counters when the proposed code must be synthesizable.

Devas

 

[shyam4908]

Re: How to generate delay?

you need a set of counter to implement the timers...

First up all u need to find the 1micro-second tick..the generation of this depends on the clock operating frequency of your circuit..for example if u r operation @ 200Mhz.. then u need to design a counter to increment for every clock and once the counter reaches 200.. a pulse is generated, which indicates 1micro-second tick..use this tick to generate millisecond.. and the millisecond count to sec counter and second count tick to generate the required timers...