The snippet below is taken from the pilot guide, with some added explanation at the bottom.

"Pressing the knob cycles through the various map views. The map view selected is indicated at the top of the map next to the heading box. 

No indication means Heading Up. 

All other options are labeled next to that heading box. 

Depending on the installation, map view options can be: 

      • Heading Up or Track Up (360°) 

      • Heading Up or Track Up (240° arc view) 

      • North Up (360°) 

Heading vs. Track selection is made from the “Map Orientation”selection on the User Options – SETUP tab of the AUX page."

Where this tends to get confusing is that there are two places to change the selection, but only one of those will change the pilots "view". 

Under "User Options" you can go to "Map Orientation" and if your IFD is being fed valid HDG information from an external source, you can select HDG Up, or Track Up.  What this does is selects which data set the map page will use to populate the HDG box at the top of the map.  If your IFD is not connected to a valid magnetic HDG source, the selection here will be "greyed out," as Track Up will be the only option.

The above setting will only change the data source used to populate the HDG box, and will not affect the map view.  The lower R/H knob, when pressed like a button, will toggle the map orientation from a default state of North Up, to HDG/Track Up depending upon whether HDG or Track is selected in the user option page.  Pressing the button again will toggle to HDG/Track Up with a 240 degree view.  Pressing the button a third time will toggle the map back to North Up orientation.