28.2.2 Auto-Baud Overflow

During the course of automatic baud detection, the ABDOVF bit of the BAUDxCON register will be set if the baud rate counter overflows before the fifth rising edge is detected on the RXx pin. The ABDOVF bit indicates that the counter has exceeded the maximum count that can fit in the 16 bits of the SPxBRGH:SPxBRGL register pair. After the ABDOVF bit has been set, the counter continues to count until the fifth rising edge is detected on the RXx pin. Upon detecting the fifth RX edge, the hardware will set the RCxIF interrupt flag and clear the ABDEN bit of the BAUDxCON register. The RCxIF flag can be subsequently cleared by reading the RCxREG register. The ABDOVF flag of the BAUDxCON register can be cleared by software directly.

To terminate the auto-baud process before the RCxIF flag is set, clear the ABDEN bit then clear the ABDOVF bit of the BAUDxCON register. The ABDOVF bit will remain set if the ABDEN bit is not cleared first.