Secondary Oscillator (SOSC)
The Secondary Oscillator (SOSC) is designed specifically for low-power operation with an external 32 to 100 KHz crystal. The oscillator is connected to the SOSCO and SOSCI device pins and serves as a secondary crystal clock source for low-power operation. It can also drive Timer1 and/or the Real-Time Clock and Calendar (RTCC) module for Real-Time Clock (RTC) applications.
The following code sample demonstrates how to (a) enable the secondary oscillator for a specific device using configuration bit settings, and (b) how to perform simple run-time modification using the MPLAB® Harmony PLIB APIs
// Enable Secondary oscillator by default #pragma config FSOSCEN = ON // default System clock = Secondary oscillator #pragma config FNOSC = SOSC // Run-time configuration using Harmony functions shown below // System Clock = SOSC (run-time config) PLIB_OSC_SysClockSelect(OSC_ID_0, OSC_SECONDARY); // Enable Secondary oscillator PLIB_OSC_SecondaryEnable(OSC_ID_0); // Disable Secondary oscillator PLIB_OSC_SecondaryDisable(OSC_ID_0);
For more detail on the Secondary Oscillator module for a specific PIC32 device, please view the Oscillator family reference manual chapter for that device, for example:
- Section 6. Oscillators (PIC32MX795F512L)
- Section 42. Oscillators with Enhanced PLL (PIC32MZ2048EFG100)
The device data sheet should then be consulted to verify the specific features implemented in that device.