Infineon Technologies TC1728 User Manual page 1152

Note: In synchronous operating mode of the ASC, the type of the selected RXD port pin
(input or output) is not automatically controlled by the ASC but must be defined by
a user program by writing the appropriate bit field in the IOCR registers.
User's Manual
ASC, V1.3 2007-11
Asynchronous/Synchronous Serial Interface (ASC)
17-40
TC1728
V1.0, 2011-12