MCU : mc9s12g128
Compiler： codewarriory 5.1
During the running of the program, the pull-up register of the port is rewritten, and the pull-up function of the port is opened after the rewriting. After checking the software did not operate this register, I would like to analyze from hardware, software, compiler, and what are the reasons for rewriting the register. How to locate the reason why the register is abnormally overwritten.