9.3 Primary Oscillator (POSC)

The dsPIC33CK256MC006 family devices contain one instance of the Primary Oscillator (POSC). The Primary Oscillator is available on the OSCI and OSCO pins of the dsPIC33CK devices. This connection enables an external crystal (or ceramic resonator) to provide the clock to the device. The Primary Oscillator provides three modes of operation:

• Medium Speed Oscillator (XT Mode): The XT mode is a Medium Gain, Medium Frequency mode used to work with crystal frequencies of 3.5 MHz to 10 MHz.
• High-Speed Oscillator (HS Mode): The HS mode is a High-Gain, High-Frequency mode used to work with crystal frequencies of 10 MHz to 32 MHz.
• External Clock Source Operation (EC Mode): If the on-chip oscillator is not used, the EC mode allows the internal oscillator to be bypassed. The device clocks are generated from an external source (0 MHz to up to 64 MHz) and input on the OSCI pin.