CC2340R2: External 32K XTAL

Tool/software:

Hi Team, 

My customer is using CC2340R2, and decide to use external 32K clock like they designed CC2640R2 before.

But they need to know the related clock signal requirements for external 32KHz clock input of CC2340R2.

Please help for the following items:

1. What is the clock signal requirements for external 32KHz clock input ?

2. If any application note can be referenced for CC2340R2/R5 ?

3. for using external 32KHz clock,  what is the design advantages ? 

Thanks.