Atmel Evaluation Kit AT91SAM9G25-EK AT91SAM9G25-EK Data Sheet
Product codes
AT91SAM9G25-EK
176
SAM9G25 [DATASHEET]
11032C–ATARM–25-Jan-13
21.5
Main Clock
Figure 21-3. Main Clock Block Diagram
The Main Clock has two sources:
z
12 MHz Fast RC Oscillator which starts very quickly and is used at startup
z
12 to 16 MHz Crystal Oscillator, which can be bypassed
XIN
XOUT
MOSCXTEN
MOSCXTCNT
MOSCXTS
Main Clock
Frequency
Counter
MAINF
MAINRDY
SLCK
Slow Clock
12-16 MHz
Crystal
Oscillator
12-16 MHz Crystal
Oscillator
Counter
MOSCRCEN
12 MHz
Fast RC
Oscillator
MOSCRCS
MOSCRCF
MOSCRCEN
MOSCXTEN
MOSCSEL
MOSCSEL
MOSCSELS
1
0
MAINCK
Main Clock