Information

UARTx_IS7816 field descriptions (continued)
Field Description
0 Block wait time (BWT) has not been violated.
1 Block wait tTime (BWT) has been violated.
4
INITD
Initial Character Detected Interrupt
This 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.
3
Reserved
This read-only field is reserved and always has the value zero.
2
GTV
Guard Timer Violated Interrupt
This flag indicates that one or more of the character guard time, block guard time or guard time were
violated. 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.
1
TXT
Transmit Threshold Exceeded Interrupt
This flag indicates that the transmit NACK threshold has been exceeded as indicated by the
ET7816[TXTHRESHOLD] field. Regardless if this flag is set, the UART will continue to retransmit
indefinitely. This flag only asserts when C7816[TTYPE] = 0. If 7816E is cleared/disabled, ANACK is
cleared/disabled, C2[TE] is cleared/disabled, C7816[TTYPE] = 1 or packet is transferred without receiving
a NACK the internal NACK detection counter is cleared and the count restarts from zero on the next
received NACK. This interrupt is cleared by writing `1'.
0 The number of retries and corresponding NACKS does not exceed the value in the
ET7816[TXTHRESHOLD] field.
1 The number of retries and corresponding NACKS exceeds the value in the ET7816[TXTHRESHOLD]
field.
0
RXT
Receive Threshold Exceeded Interrupt
This flag indicates that there were more than ET7816[RXTHRESHOLD] consecutive NACKS generated in
response to parity errors on received data. This flag requires ANACK to be set. Additionally, this flag only
asserts when C7816[TTYPE] = 0. Clearing this bit also resets the counter keeping track of consecutive
NACKS. The UART will continue to attempt to receive data regardless of if this flag is set. If 7816E is
cleared/disabled, RE is cleared/disabled, C7816[TTYPE] = 1 or packet is received without needing to
issue a NACK, the internal NACK detection counter is cleared and the count restarts from zero on the
next 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 less
than or equal to the value in ET7816[RXTHRESHOLD].
1 The number of consecutive NACKS generated as a result of parity errors and buffer overruns is
greater than the value in ET7816[RXTHRESHOLD].
Memory map and registers
K10 Sub-Family Reference Manual, Rev. 6, Nov 2011
1292 Freescale Semiconductor, Inc.