18.5.8 Waveform Generation

Waveforms can be generated in order to take advantage of the RTC inherent prescalers while the RTC is the only powered circuitry (Low-power mode of operation, Backup mode) or in any active mode. Entering Backup or Low-power operating modes does not affect the waveform generation outputs.

The RTC waveforms are internally routed to ADC trigger events and those events have a source driver selected among five possibilities. Two different triggers can be generated at a time, the first one is configurable in RTC_MR.OUT0, while the second trigger is configurable in RTC_MR.OUT1. RTC_MR.OUT0 manages the trigger for channel AD[n:0] (where n is the higher index available (last channel)), while RTC_MR.OUT1 manages the channel AD[n] only for specific modes. Refer to ADC_MR.TRGSEL in section “Analog-to-Digital Converter (ADC) Controller” for selection of the measurement triggers and associated modes of operation.

When RTC_MR.OUTx is set to 0, the associated output is stuck at 0 (reset value that can be used at any time to disable the waveform generation).