In your opinion, Which code viewer is better?
this is the code viewer of the Stack:
and this is another code viewer:
Really Why doesn't the Stack has a good code viewer?
You have two problems. The first is that you're confusing StackExchange with an IDE.
The code highlighting doesn't work on your question here because you have put a whole lot of relatively worthless tags on your question instead of one that defines the language you are using. For example, if you used c instead of each individual microcontroller you used, you wouldn't have an issue. I have changed your tags and now syntax highlighting shows up.