Data segment in C

Data segment in C is broadly classified in 4 sections: ".txt" , ".rodata" , ".bss" , ".data"

.rodata:The .rodata is also used for storing string constants and read only data's.

.data:The compiler places initialized and uninitialized global variables in the .data section.
.bss: A separate section called .bss is used for uninitialized variables or temporary variable in stack
.txt: Opcode i.e executable code is stored in this section.

Note:Flash content cannot be modified, it can only be erased and re-written hence code and constants are stored in flash while variables are stored in RAM.