In regards to the 32.768 kHz oscillator (the 32K_PWM_IN) signal on the Sterling-LWB, is it required to bring up the oscillator before bringing up the power rails on the module or is that timing not critical?

Answer

On our reference designs, the 32KHz oscillator is powered up at the same time as the module power rails. We do not recommend exercising I/O on an un-powered device.