Nstimer not fired when call from Titanium in ios module

Hi

I am calling a method from Titanium .js file to ios native class using ios module.

In native method, I am calling Nstimer. But Nstimer method is not firing at all.

timer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(startThread) userInfo:nil repeats:YES];

Please help me

Thanks