Various external clock inputs/outputs are needed to drive the device. Summary of these input clock signals is as follows:
- High frequency oscillators inputs
- OSC1_XO/OSC1_XI — external main crystal interface pins connected to internal oscillator which sources reference clock. Provides reference clock to PLLs within MCU domain and MAIN domain. This high-frequency oscillator is used to provide audio clock frequencies to MCASPs.
- WKUP_OSC0_XO/WKUP_OSC0_XI — external main crystal interface pins connected to internal oscillator which sources reference clock. Provides reference clock to PLLs within WKUP and MAIN domain.
- Low frequency digital input
- WKUP_LF_CLKIN - Low
Frequency 32k digital clock input, optionally sourced from an external
PMIC or other clock source. This SoC does not support a LFOSC crystal
input.
- General purpose clock inputs
- MCU_EXT_REFCLK0 - optional external System clock input (MCU domain).
- EXT_REFCLK1 — optional external System clock
input (MAIN domain).
- Peripheral clocks - refer to the Signal Descriptions for peripheral specific
clocks
For more information about
Input clock interfaces, see Clocking section in Device Configuration
chapter in the device TRM.