Clock Overview

[中文]

The system clock sources include:

  • ROSC

  • XTAL-32K

  • XTAL-40M

  • DPLL

Note: XTAL means external crystal clock:

  • XTAL-32K: external 32K

  • XTAL-40M: external 40M

The system includes external 40M by default. External 32K can be added based on project requirements.

Clock Configuration

32K clock sources include:

  • ROSC

Advantages and disadvantages: Low power consumption, but relatively poor clock accuracy. It is suitable for achieving minimum power consumption.

  • 32K derived from external 40M division

Advantages and disadvantages: Good precision, but relatively higher power consumption.

  • External 32K crystal clock

Advantages and disadvantages: Good precision, and lower power consumption than 32K derived from external 40M division, but it requires an additional external 32K crystal.

Therefore, different 32K clock sources can be selected based on business requirements and usage scenarios.

DPLL Usage

DPLL is generated by frequency multiplication from the external 40M clock.

  • WIFI uses DPLL during active operation.

  • BLE uses DPLL during active operation.

  • Different DPLL divided clocks can be selected based on business requirements to save power.