6501 digital input levels

Hello,

I am using 6501 port 1 to read digital logic of my circuit output.  In 6501  port pins  have +5V and 4.7K pull-up resistors. Up to what voltage on the port pin (configured as digital input), 6501 declare as LOW and  HIGH?. I read elsewhere that voltage between 0 to 0.8V will be  reported as logic 0 and voltage above 2V will be reported as  Logic high. Is this correct?

Thanks,

Leyo Joseph