SAM3U Datasheet, PDF (39/59 Pages) ATMEL Corporation – AT91SAM ARM-based Flash MCU

SAM3U Series
10.6 Power Management Controller
The Power Management Controller provides all the clock signals to the system. It provides:
• 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 Device HS Clock UDPCK
• independent peripheral clocks, typically at the frequency of MCK
• three programmable clock outputs: PCK0, PCK1 and PCK2
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.
Figure 10-3. Power Management Controller Block Diagram
Processor
Clock
Controller
Sleep Mode
HCK
int
SLCK
MAINCK
PLLACK
PLLBCK
Master Clock Controller
Prescaler
/1,/2,/4,...,/64
Divider
/8
SystTick
FCLK
Peripherals
Clock Controller
ON/OFF
MCK
periph_clk[..]
Programmable Clock Controller
SLCK
MAINCK
PLLACK
PLLBCK
ON/OFF
Prescaler
/1,/2,/4,...,/64
HSCK
USB Clock Controller
ON/OFF
pck[..]
UDPCK
The SysTick calibration value is fixed at 10500, which allows the generation of a time base of
1 ms with SystTick clock to 10.5 MHz (max HCLK/8).
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6430ES–ATARM–22-Aug-11