SWCU192 November 2021 CC1312R7 , CC1352P7 , CC2652P7 , CC2652R7
The AON_RTC:SYNC register synchronizes between the MCU domain and AON domain.
A read request from the AON_RTC:SYNC register does not return if there are outstanding write requests to the AON registers; in other words, the bus is halted until all outstanding requests are completed.
A write request triggers a dummy write to the AON domain. This write can ensure synchronization to the MF clock. This dummy write takes one to two 2 MHz MF clock cycles.
The AON_RTC:SYNC register operation is typically used when a specific order must be ensured. For example, when disabling a channel, the AON_RTC:SYNC register can be polled to ensure that the channel has been disabled and no further events can occur:
Another typical use is to ensure the correct values are updated in the MCU domain on wakeup. This MCU domain is only updated on a positive edge of the 2 MHz MF clock.