The Clock Generator is comprised of the following:
- A low-power 32.768 kHz crystal oscillator with Bypass mode
- A low-power Slow RC oscillator (32 kHz typical)
- A 3 to 20 MHz Main crystal oscillator
with Bypass mode
- A Main RC oscillator. Three output frequencies can be selected:
4/8/12
MHz. By default 12 MHz is selected. 8 MHz and 12 MHz are
factory-trimmed.
- A 480 MHz UTMI PLL, providing a clock for the USB high-speed
controller
- A 160 to 500 MHz programmable PLL (input
from 8 to 32 MHz)
It provides the following clocks:
- SLCK — Slow clock. The only permanent clock within the system
- MAINCK — output of the Main clock oscillator selection: either
the Main crystal oscillator or Main RC oscillator
- PLLACK — output of the divider and 160 to 500 MHz programmable PLL (PLLA)
- UPLLCK — output of the 480 MHz UTMI PLL (UPLL)