28.4.2 32.768 kHz Crystal Oscillator

By default, the 32.768 kHz oscillator is disabled. To use this oscillator, the XIN32 and XOUT32 pins must be connected to a 32.768 kHz crystal or to a ceramic resonator. Refer to the section “Electrical Characteristics” for appropriate loading capacitors selection on XIN32 and XOUT32.

To select the 32.768 kHz crystal oscillator as the source of TD_SLCK, SCKC_CR.TD_OSCSEL must be set to 1. The switch of TD_SLCK source is glitch-free.

The user can also set the 32.768 kHz crystal oscillator in Bypass mode instead of connecting a crystal. In this case, the user must provide the external clock signal on XIN32. For input characteristics of the XIN32 pin, refer to the section “Electrical Characteristics”. To enter Bypass mode, the OSC32BYP bit of the Slow Clock Controller Configuration register (SCKC_CR) must be set to 1 prior to setting SCKC_CR.TD_OSCSEL.