SPRUHZ7K August 2015 – April 2024 AM5706 , AM5708 , AM5716 , AM5718 , AM5718-HIREL
A buffer overrun occurs when a serializer is instructed to transfer data from XRSRn shift register to XRBUFn receiver buffer, but the corresponding MCASP_RXBUFn register has not yet been read since the last time the transfer occured. When this occurs, the receiver state machine sets the overrun flag - ROVRN. However, the individual serializer writes over the data in the XRBUFn buffer register (destroying the previous sample) and continues shifting.
An overrun is checked only once per time slot. The MCASP_RXSTAT[0] ROVRN flag is set when an overrun condition occurs. It is possible that an overrun occurs on one time slot but then the host catches up and does not cause an overrun on the following time slots. However, once the ROVRN flag is set, it remains set until the host explicitly writes a 1 to the ROVRN bit to clear the ROVRN bit.