SAM3S ATMEL [ATMEL Corporation], SAM3S Datasheet - Page 38

• Manufacturer Part Number: SAM3S
• Description: ARM-based Flash MCU
• Manufacturer: ATMEL [ATMEL Corporation]

Figure 10-2. Clock Generator Block Diagram
10.6
38
Power Management Controller
SAM3S Summary
The Power Management Controller provides all the clock signals to the system. It provides:
The Supply Controller selects between the 32 kHz RC oscillator or the crystal oscillator. The
unused oscillator is disabled automatically so that power consumption is optimized.
By default, at startup the chip runs out of the Master Clock using the fast RC oscillator running at
4 MHz.
The user can trim the 8 and 12 MHz RC Oscillator frequency by software.
• the Processor Clock, HCLK
• the Free running processor clock, FCLK
• the Cortex SysTick external clock
• the Master Clock, MCK, in particular to the Matrix and the memory interfaces
• the USB Clock, UDPCK
• independent peripheral clocks, typically at the frequency of MCK
• three programmable clock outputs: PCK0, PCK1 and PCK2
XOUT32
XIN32
XOUT
XIN
Management
12/8/4 MHz
Slow Clock
3-20 MHz
Oscillator
RC OSC
Divider A
Controller
Clock Generator
PLL and
Oscillator
PLL and
Divider B
RC OSC
On Chip
On Chip
32 kHz
Power
Status
Main
Control
XTALSEL
Slow Clock
SLCK
Main Clock
MAINCK
MAINSEL
PLLB Clock
PLLBCK
PLLA Clock
PLLACK
6500CS–ATARM–24-Jan-11