9.6.3 General Read-Synchronization

Read-Synchronized registers are synchronized each time the register value is updated, but the corresponding Synchronization Busy (SYNCBUSY) register bits are not set. Reading a read-synchronized register does not start a new synchronization; it returns the last synchronized value.

Note: The corresponding bits in SYNCBUSY will automatically be set when the device wakes up from a sleep mode, because read-synchronized registers must be synchronized. For this reason, reading a read-synchronized register before its corresponding SYNCBUSY bit is cleared will return the last synchronized value from before entering a sleep mode.

However, if a register is also write-synchronized, any write access while the SYNCBUSY bit is set will be executed successfully.