I will put it this way. When an output pin is high and connected to a lower potential, it can stand up to about 40mA flowing out of the pin. When an output pin is high and connected to a higher potential, it can stand up to 2mA flowing into the pin. When an output pin is low and connected to a lower potential, it can stand up to 2mA flowing out of the pin. When an output pin is low and connected to a higher potential, it can stand up to about 40mA flowing into the pin.
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