Q: The RTC chapter of the HRM (UG-587) mentions a "1 Hz domain". Is this a typo or is there in fact a 1 Hz domain?
A: The references to "1 Hz domain" really mean the "32 kHz clock domain in which 1 Hz real-time counting and prescaling is carried out". The 32 kHz clock is prescaled down to 1 Hz and the integer part of the RTC updates at a rate of 1 Hz, but all such operations (prescaling and counting) are synchronous to 32 kHz. Synchronisation is to and from the 32 kHz clock (LFXTAL).