14.3.1.3 Read-Synchronization

Reading a read-synchronized peripheral core register will cause the peripheral bus to stall immediately until the read-synchronization is complete. STATUS.SYNCBUSY will not be set. Refer to Synchronization Delay for details on the synchronization delay. Note that reading a read-synchronized peripheral core register while STATUS.SYNCBUSY is one will cause the peripheral bus to stall twice; first because of the ongoing synchronization, and then again because reading a read-synchronized core register will cause the peripheral bus to stall immediately.