This anomaly applies to Engineering A, build code QFAA-Axx.
Symptoms
Wrong number of transferred bytes is reported.
Conditions
During the handling of the RXTO event, FLUSHRX is performed and the number of transferred bytes does not exceed MAXCNT.
Consequences
UARTE operations are unreliable.
Workaround
Apply the following workaround:
/* Setup buffer to which data can be flushed. */
UARTE->DMA.RX.PTR = buf;
UARTE->DMA.RX.MAXCNT = 5;
/* Clear READY. Needed for the workaround. */
UARTE->EVENTS_DMA.RX.READY = 0;
UARTE->EVENTS_DMA.RX.END = 0;
/* Trigger flushing. */
UARTE->TASKS_FLUSHRX = 1;
/* Wait until flushing is done. */
while (UARTE->EVENTS_DMA.RX.END == 0);
/* If READY event is set then use AMOUNT value else FIFO was empty.
If not for the PAN, AMOUNT could be read without checking READY event. */
fifo_cnt = (UARTE->EVENTS_DMA.RX.READY == 1) ? UARTE->DMA.RX.AMOUNT : 0;