[Phalanx]

As others have stated there is no "official" style. Again as others have stated pick a style and stick to it. Being consistent throughout is a bigger benefit than it is usually given credit for.

There's an old saying that I found to be true...
"Programmers don't need to spell correctly, just consistently"

What we have opted for is below with a few exceptions.
lower_case_variable_name
UPPER_CASE_DEFINE_MACRO
Mixed_Case_Function_Call()
We indent everything at each level for clarity as well.

We've also adapted a philosophy of modular code design so we can have different programmers working on different functions concurrently and independently. All functions have "Get" and "Set" functions to allow programmers to access values from each function without needing to access a variable directly.

some examples...

#DEFINE ZERO 0
int x = 0;
x = Get_Left_Encoder_Count();
Set_Left_Encoder_Count(ZERO);
if (p1_y == 127)
    {
    pwm01 = 127;
    }
else
    {
    pwm01 = p1_y;
    }