dsPIC33EP16GS504 configuration bits

The configuration words set the oscillator and PLL, the watchdog, the debugger pins, brown-out reset and code protection: they sit in their own configuration memory at 0xF80000. Pick a setting and the word below updates; the starting values are the defaults in Microchip's device file, and an erased bit reads 1. In XC16 each setting is a #pragma config FNOSC = FRC line.