19.2 Embedded Characteristics

The Clock Generator is made up of:

• Oscillators
  • A low-power 32.768 kHz oscillator supporting crystals, MEMs, resonators and Bypass mode
    Note: This oscillator is referred to as 32.768 kHz Crystal Oscillator throughout the document.
  • An embedded always-on, slow RC oscillator generating a typical 32 kHz clock
  • A 12 to 48 MHz oscillator supporting crystals, MEMs, resonators and Bypass mode
    Note: This oscillator is referred to as Main Crystal Oscillator throughout the document.
  • A Main RC oscillator generating a typical 12 MHz clock
• Three fractional-N PLLs

It provides the following clocks:

• MD_SLCK—Monitoring Domain Slow clock. This clock, sourced from the always-on Slow RC oscillator only, is the only permanent clock of the system and feeds safety-critical functions of the device (DWDT, RSTC, SUPC, frequency monitors and detectors, PMC start-up time counters).
• TD_SLCK—Timing Domain Slow clock. This clock, sourced from the 32.768 kHz crystal oscillator or the always-on Slow RC oscillator, is routed to the RTC and RTT peripherals.
• MAINCK—Output of the Main clock oscillator selection. This clock is either the Main crystal oscillator or Main RC oscillator.
• PLL Clocks—Outputs of embedded PLLs
• One SysTick external clock for each Processor core