HIGH will
set the Port 0 pin corresponding to expression to a positive
value (3.3V).
HIGH does not change the direction of the port 0 pin, ie. it must be set to an OUTPUT before HIGH has any affect.
With the SuperPRO and PROplus, NXP has added more configurable port pins. We are adopting their convention for control of those pins. FIO0SET, FIO1SET, FIO2SET, and FIO4SETwill set an output high when written with a 1. More details in the NXP user manuals.