11.1.1.5.1 SOSC Power Modes

Two Power modes are available for the secondary oscillator and are selected using the Secondary Oscillator Power Mode Select (SOSCPWR) bits. When the SOSCPWR bits are clear (SOSCPWR = 'b00), the oscillator operates in Low-Power mode, which is ideal for crystal oscillators with low drive strength. When the SOSCPWR bits are configured to ''b01', the oscillator operates in Medium-Power mode, which is ideal for crystal oscillator with medium drive strength. When the SOSCPWR bits are set to either ''b10' or ''b11', the oscillator operates in High-Power mode, which is ideal for crystal oscillators with high drive strength or high Equivalent Series Resistance (ESR). The recommended maximum values for the crystal oscillator's ESR and load capacitance are shown in the table below.

Important: The SOSC module must be disabled before changing Power modes. Changes to the Power mode during operation may result in undefined oscillator behavior.
Table 11-2. Recommended Maximum Crystal Characteristics
Power ModeCrystalCircuit

ESR

(Max Ω)

C0

(Max pF)

CLOAD

(max pF)

High100 k218
Medium70 k212.5
Low50 k28
Note:
  1. Crystal frequency: 32.768 kHz
  2. ESR: Equivalent Series Resistance
  3. C0: shunt capacitance
  4. CLOAD includes pin capacitance