Driving down the road and truck just dies

I was driving down the road yesterday. Turned off of gravel to blacktop got up to 55 mph when my F-150, 5.4L Triton, died. No warning lights, no out of normal gauges, etc. I immediately pulled over. Once on the side of the road and stopped I tried to restart - nothing.

Got pulled to a shed. The lights, electric locks/windows, radio, headlights, etc. Are working fine. When I turn the key to start there is nothing. Looked all fuses over and are OK, the battery is at 12.5V (no corrosion on terminals or connections). Thought it might be the alternator but with the battery ok everyone figured it wasn't that. Put a dynastic reader on under the dash got no reading.