46.3.25 UART 7816 Interrupt Status Register (UARTx_IS7816)
The IS7816 register provides a mechanism to read and clear the interrupt flags. All flags/
interrupts are cleared by writing a 1 to the field location. Writing a 0 has no effect. All
bits are "sticky", meaning they indicate that only the flag condition that occurred since
the last time the bit was cleared, not that the condition currently exists. The status flags
are set regardless of whether the corresponding field in the IE7816 is set or cleared. The
IE7816 controls only if an interrupt is issued to the host processor. This register is
specific to 7816 functionality and the values in this register have no affect on UART
operation and should be ignored if 7816E is not set/enabled. This register may be read or
written at anytime.
Address: Base a 1Ah offset
Bit
7
6
5
4
3
2
1
0
Read
Write
Reset
0
0
0
0
0
0
0
0
UARTx_IS7816 field descriptions
Field
Description
7
WT
Wait Timer Interrupt
Indicates that the wait time, the time between the leading edge of a character being transmitted and the
leading edge of the next response character, has exceeded the programmed value. This flag asserts only
when C7816[TTYPE] = 0. This interrupt is cleared by writing 1.
0
Wait time (WT) has not been violated.
1
Wait time (WT) has been violated.
6
CWT
Character Wait Timer Interrupt
Indicates that the character wait time, the time between the leading edges of two consecutive characters
in a block, has exceeded the programmed value. This flag asserts only when C7816[TTYPE] = 1. This
interrupt is cleared by writing 1.
0
Character wait time (CWT) has not been violated.
1
Character wait time (CWT) has been violated.
5
BWT
Block Wait Timer Interrupt
Indicates that the block wait time, the time between the leading edge of first received character of a block
and the leading edge of the last character the previously transmitted block, has exceeded the programmed
value. This flag asserts only when C7816[TTYPE] = 1.This interrupt is cleared by writing 1.
0
Block wait time (BWT) has not been violated.
1
Block wait time (BWT) has been violated.
4
INITD
Initial Character Detected Interrupt
Indicates that a valid initial character is received. This interrupt is cleared by writing 1.
Table continues on the next page...
Memory map and registers
K22F Sub-Family Reference Manual , Rev. 3, 7/2014
1164
Freescale Semiconductor, Inc.