46.9.6 Legacy and reverse compatibility considerations
Recent versions of the UART have added several new features. Whenever reasonably
possible, reverse compatibility was maintained. However, in some cases this was either
not feasible or the behavior was deemed as not intended. This section describes several
differences to legacy operation that resulted from these recent enhancements. If
application code from previous versions is used, it must be reviewed and modified to take
the following items into account. Depending on the application code, additional items
that are not listed here may also need to be considered.
1. Various reserved registers and register bits are used, such as, MSFB and M10.
2. This module now generates an error when invalid address spaces are used.
3. While documentation indicated otherwise, in some cases it was possible for
S1[IDLE] to assert even if S1[OR] was set.
4. S1[OR] will be set only if the data buffer (FIFO) does not have sufficient room.
Previously, the data buffer was always a fixed size of one and the S1[OR] flag would
set so long as S1[RDRF] was set even if there was room in the data buffer. While the
clearing mechanism has remained the same for S1[RDRF], keeping the OR flag
assertion tied to the RDRF event rather than the data buffer being full would have
greatly reduced the usefulness of the buffer when its size is larger than one.
5. Previously, when C2[RWU] was set (and WAKE = 0), the IDLE flag could reassert
up to every bit period causing an interrupt and requiring the host processor to reassert
C2[RWU]. This behavior has been modified. Now, when C2[RWU] is set (and
WAKE = 0), at least one non-idle bit must be detected before an idle can be detected.
Application information
KV4x Reference Manual, Rev. 2, 02/2015
1326
Preliminary
Freescale Semiconductor, Inc.
Содержание freescale KV4 Series
Страница 2: ...KV4x Reference Manual Rev 2 02 2015 2 Preliminary Freescale Semiconductor Inc...
Страница 60: ...KV4x Reference Manual Rev 2 02 2015 60 Preliminary Freescale Semiconductor Inc...
Страница 82: ...JTAG Controller Configuration KV4x Reference Manual Rev 2 02 2015 82 Preliminary Freescale Semiconductor Inc...
Страница 88: ...System Register file KV4x Reference Manual Rev 2 02 2015 88 Preliminary Freescale Semiconductor Inc...
Страница 128: ...Debug Security KV4x Reference Manual Rev 2 02 2015 128 Preliminary Freescale Semiconductor Inc...
Страница 138: ...Boot KV4x Reference Manual Rev 2 02 2015 138 Preliminary Freescale Semiconductor Inc...
Страница 150: ...Pinout diagrams KV4x Reference Manual Rev 2 02 2015 150 Preliminary Freescale Semiconductor Inc...
Страница 170: ...Functional description KV4x Reference Manual Rev 2 02 2015 170 Preliminary Freescale Semiconductor Inc...
Страница 212: ...Functional description KV4x Reference Manual Rev 2 02 2015 212 Preliminary Freescale Semiconductor Inc...
Страница 284: ...Functional description KV4x Reference Manual Rev 2 02 2015 284 Preliminary Freescale Semiconductor Inc...
Страница 294: ...Functional description KV4x Reference Manual Rev 2 02 2015 294 Preliminary Freescale Semiconductor Inc...
Страница 330: ...Functional description KV4x Reference Manual Rev 2 02 2015 330 Preliminary Freescale Semiconductor Inc...
Страница 450: ...Initialization application information KV4x Reference Manual Rev 2 02 2015 450 Preliminary Freescale Semiconductor Inc...
Страница 512: ...Interrupts and DMA Requests KV4x Reference Manual Rev 2 02 2015 512 Preliminary Freescale Semiconductor Inc...
Страница 520: ...Memory Map and Register Descriptions KV4x Reference Manual Rev 2 02 2015 520 Preliminary Freescale Semiconductor Inc...
Страница 580: ...Initialization Application information KV4x Reference Manual Rev 2 02 2015 580 Preliminary Freescale Semiconductor Inc...
Страница 660: ...Functional description KV4x Reference Manual Rev 2 02 2015 660 Preliminary Freescale Semiconductor Inc...
Страница 1038: ...Example configuration for chained timers KV4x Reference Manual Rev 2 02 2015 1038 Preliminary Freescale Semiconductor Inc...
Страница 1074: ...Functional description KV4x Reference Manual Rev 2 02 2015 1074 Preliminary Freescale Semiconductor Inc...
Страница 1168: ...Initialization application information KV4x Reference Manual Rev 2 02 2015 1168 Preliminary Freescale Semiconductor Inc...
Страница 1264: ...Initialization application information KV4x Reference Manual Rev 2 02 2015 1264 Preliminary Freescale Semiconductor Inc...
Страница 1336: ...Functional description KV4x Reference Manual Rev 2 02 2015 1336 Preliminary Freescale Semiconductor Inc...
Страница 1358: ...KV4x Reference Manual Rev 2 02 2015 1358 Preliminary Freescale Semiconductor Inc...