1. In the Atmels data sheet for the AT89S8252 it states that each pin of port 0 can sink up to 8 ttl inputs and 4ttl inputs for other ports that got internal pullups. how much is that in mA?
2. I have leads 30 cm long (including pcb tracks) from ports to external switches. Do I need pullup resistor for the ports that are not open drain.
3. What should the value of pull up resistor be and is it needed for ports that got internal pullups as indicated in 2 above ?
Thanx