This f counter used pll ic from national (lmx2346) and capable to measure freq up to 2.5 Ghz. This ic used to divided freq input by 64 and programmed by spi interface by microcontroller. The freq input will change the charge pump, its ttl leveler. This charge pump (Cpo) will directly connected to microcontroller and measured the freq by microcontroller.
I got no problem to interface lcd, and programmed pll ic with this microcontroller.
The problem is i don't know how to start to measure the freq was converted to by charge pump and connected to RC0 of microcontroller.