Hi,
the drive strength is related to used current and driving possibilities of the specific pins. It defines how much is the pin MOSFET opened so how much current is able to supply to load together with defined voltage drop at the pin. (It is related also to calculation of the total power dissipation PD - Chapter A.1.6)
Some more info can be found in chapter 2.3.3.9 Reduced Drive Register:
RDRx7-0
Reduced Drive Register — Select reduced drive for output pin
This bit configures the drive strength of the associated output pin as either full or reduced. If a pin is used as input
this bit has no effect. The reduced drive function is independent of which function is being used on a particular pin.
1 Reduced drive selected (approx. 1/10 of the full drive strength)
0 Full drive strength enabled
Best regards,
Ladislav
