+ /* Delay for 'a while' waiting for the crystal to
+ * stabilize -- the XOSC_STB bit isn't reliable
+ *
+ * http://www.ti.com/lit/er/swrz022c/swrz022c.pdf
+ */
+
+ ao_clock_delay();
+
+ /* Switch system clock to crystal oscilator */
+ CLKCON = (CLKCON & ~CLKCON_OSC_MASK) | (CLKCON_OSC_XTAL);
+