8.3.7.3.7 Receiver Operations
When a character reception is completed, it is transferred to the Receive Holding register (FLEX_US_RHR) and the FLEX_US_CSR.RXRDY bit is raised. If a character is completed while the RXRDY is set, the Overrun Error (OVRE) bit is set. The last character is transferred into FLEX_US_RHR and overwrites the previous one. The OVRE bit is cleared by writing a one to Reset Status bit FLEX_US_CR.RSTSTA.