#define AT91_PMC_MCFR_MAINRDY 0x00010000
#define AT91_PMC_MCFR_MAINF_MASK 0x0000FFFF
+#define AT91_PMC_MCFR_RCMEAS 0x00100000
+#define AT91_PMC_MCFR_CCSS_XTAL_OSC 0x01000000
#define AT91_PMC_MCKR_CSS_SLOW 0x00000000
#define AT91_PMC_MCKR_CSS_MAIN 0x00000001