NXP Semiconductors freescale K51 Series Reference Manual

UARTx_IS7816 field descriptions (continued)Field Description0 Block wait time (BWT) has not been violated.1 Block wait tTime (BWT) has been violated.4INITDInitial Character Detected InterruptThis flag indicates that a valid initial character was received. This interrupt is cleared by writing `1'.0 A valid initial character has not been received.1 A valid initial character has been received.3ReservedThis read-only field is reserved and always has the value zero.2GTVGuard Timer Violated InterruptThis flag indicates that one or more of the character guard time, block guard time or guard time wereviolated. This interrupt is cleared by writing `1'.0 A guard time (GT, CGT or BGT) has not been violated.1 A guard time (GT, CGT or BGT) has been violated.1TXTTransmit Threshold Exceeded InterruptThis flag indicates that the transmit NACK threshold has been exceeded as indicated by theET7816[TXTHRESHOLD] field. Regardless if this flag is set, the UART will continue to retransmitindefinitely. This flag only asserts when C7816[TTYPE] = 0. If 7816E is cleared/disabled, ANACK iscleared/disabled, C2[TE] is cleared/disabled, C7816[TTYPE] = 1 or packet is transferred without receivinga NACK the internal NACK detection counter is cleared and the count restarts from zero on the nextreceived NACK. This interrupt is cleared by writing `1'.0 The number of retries and corresponding NACKS does not exceed the value in theET7816[TXTHRESHOLD] field.1 The number of retries and corresponding NACKS exceeds the value in the ET7816[TXTHRESHOLD]field.0RXTReceive Threshold Exceeded InterruptThis flag indicates that there were more than ET7816[RXTHRESHOLD] consecutive NACKS generated inresponse to parity errors on received data. This flag requires ANACK to be set. Additionally, this flag onlyasserts when C7816[TTYPE] = 0. Clearing this bit also resets the counter keeping track of consecutiveNACKS. The UART will continue to attempt to receive data regardless of if this flag is set. If 7816E iscleared/disabled, RE is cleared/disabled, C7816[TTYPE] = 1 or packet is received without needing toissue a NACK, the internal NACK detection counter is cleared and the count restarts from zero on thenext transmitted NACK. This interrupt is cleared by writing `1'.0 The number of consecutive NACKS generated as a result of parity errors and buffer overruns is lessthan or equal to the value in ET7816[RXTHRESHOLD].1 The number of consecutive NACKS generated as a result of parity errors and buffer overruns isgreater than the value in ET7816[RXTHRESHOLD].Memory map and registersK51 Sub-Family Reference Manual, Rev. 6, Nov 20111254 Freescale Semiconductor, Inc.