>Maximum output current sunk by any I/O pin:                       25 mA
>Maximum output current sourced by any I/O pin:                    25 mA
>Maximum current sunk by PORTA, PORTB, and PORTE (combined):      200 mA
>Maximum current sourced by PORTA, PORTB, and PORTE (combined):   200 mA
>Maximum current sunk by PORTC and PORTD (combined):              200 mA
>Maximum current sourced by PORTC and PORTD (combined):           200 mA
>
>Since sourced and sunk currents are the same, where does a beginner that
>is only reading the data sheets learn that grounding is better?  Or is
>it reflected in a different characteristic?

Check the voltage drop across the internal transistor under these
conditions. For example I am looking at page 184 of the 16F87x data sheet
DS30292c and to source 25ma at 5V supply, the output voltage has dropped to
2.5V On page 185 for the output to sink 25mA at 5V supply, the output
voltage will rise to 0.8V. So in one case the internal transistor will have
2.5V across it, in the other 0.8V

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