![NXP Semiconductors MKL27Z128VFM4 Reference Manual Download Page 743](http://html1.mh-extra.com/html/nxp-semiconductors/mkl27z128vfm4/mkl27z128vfm4_reference-manual_1721847743.webp)
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. 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.
Chapter 38 Universal Asynchronous Receiver/Transmitter(UART)
KL27 Sub-Family Reference Manual , Rev. 5, 01/2016
Freescale Semiconductor, Inc.
743