Mesa PWM carrier frequency

I was wondering what the PWM carrier frequency was for a standard Mesa card (7i76e / 7i92)?

I have managed to build bitfiles and see how they are {sort of} put together, but was wondering if there was something relating to the PWM carrier frequency.

Thanks in advance for your time and direction.

The PWM frequency is settable in hal (from a few Hz to ~400 KHz)

Thanks very much {thought it had to be set in the bitfile}, that makes life a lot easier as I've got a few things in need of a PWM signal.