535
SAM4CP [DATASHEET]
43051E–ATPL–08/14
30.
Power Management Controller (PMC)
30.1
Description
The Power Management Controller (PMC) optimizes power consumption by controlling all system and user peripheral
clocks. The PMC enables/disables the clock inputs to many of the peripherals and the Cortex-M4 Processor.
The Supply Controller selects between the 32 kHz RC oscillator or the slow 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 frequencies by software.
30.2
Embedded Characteristics
The Power Management Controller provides the following clocks:
MCK, the Master Clock, programmable from a few hundred Hz to the maximum operating frequency of the device.
It is available to the modules running permanently, such as the Enhanced Embedded Flash Controller.
Processor Clock (HCLK) and Coprocessor (second processor) Clock (CPHCLK), automatically switched off when
entering the processor in Sleep Mode.
Free running Processor Clock (FCLK) and Free running Coprocessor Clock (CPFCLK).
One SysTick external clock for each Cortex-M4 core.
Peripheral Clocks, provided to the embedded peripherals (USART, SPI, TWI, TC, etc.) and independently
controllable.
Programmable Clock Outputs (PCKx), selected from the clock generator outputs to drive the device PCK pins.
Register Write Protection.
The Power Management Controller also provides the following operations on clocks:
A main crystal oscillator clock failure detector.
A 32768 Hz crystal oscillator frequency monitor.
A frequency counter on main clock and an on-the-fly adjustable main RC oscillator frequency.