I don't know about advertisement data but if all you want is to time something then there are two ways of doing it. One, you can use millis() or micros(). They are part of the standard arduino language. I don't have a link but it should be easy to google.
unsigned long startATimer=0;
if( iWantToMarkThisParticularPointInTime )
if( millis() - startATimer > 100 )
//do what I want
You get the general idea.
Or, use the second method, use one of the timers that are built into the Atmega 328p. Unfortunately, I don't know how to do this with the Bean. I tried last summer but couldn't get it to work.