ARM的手册上有关于大小端的描述，如下：
The processor can access data words in memory in little-endian format or big-endian
format. It always accesses code in little-endian format.
Note：
Little-endian is the default memory format for ARM processors.
The processor can access data words in memory in little-endian format or big-endian
format. It always accesses code in little-endian format.
Note：
Little-endian is the default memory format for ARM processors.
STM32是固定配置为小端的
The bytes are coded in memory in Little Endian format. The lowest numbered byte in a word is considered the word’s least significant byte and the highest numbered byte the most significant.
The bytes are coded in memory in Little Endian format. The lowest numbered byte in a word is considered the word’s least significant byte and the highest numbered byte the most significant.