The system oscillator (SYSOSC) is an on-chip, accurate 24MHz frequency .
Key features of the SYSOSC include:
- High accuracy when using optional frequency correction loop (FCL) and reference resistor
- The frequency correction loop may support correction via an external resistor (ROSC) or an internal resistor, depending on the device capabilities. Refer to the device-specific data sheet to determine if a device supports the FCL with an internal or external resistor, or both
- Fast start-up time from a disabled state
- Capable of switching from base frequency to low frequency, or low frequency to base frequency
- Phase-aligned transition to minimize disturbance to peripherals
- Fast settling to specified accuracy
- A secondary output with a constant 4MHz frequency for use by MFCLK
- When fSYSOSC = 24MHz, the 4MHz output is derived from SYSOSC divided digitally by 6. SYSCTL manages the digital divider on this output to ensure a constant 4MHz output regardless of the selected SYSOSC frequency.
The SYSOSC is active at base frequency (24MHz) by default after a brownout reset, sourcing MCLK.