Difficult pointer definition 1

[Dawee1]

Hello,
I have problem to understand the code below:

#define LCD_DATA_REG (*(unsigned char*)( 0xC000 )) // Data Register
#define LCD_CTRL_REG (*(unsigned char*)( 0x8000 )) // CTRL Register

I know basics about pointers and I know how to understand pointers to functions, arrays, structures, int, ... However
I don't understand these definitions at all. Would anybody of you be so kind to explain me what these lines of code
means in detail? I would be very glad if you'll explain it step by step:

1. (unsigned char*)( 0xC000 ) - can number (0xC000) be a pointer? or what does this line mean?
2. (*(unsigned char*)( 0xC000 )) - what does the other symbol * mean?
...

Thank you and sorry for bothering you with this maybe easy problem.

 

[chipperMDW]

0xC000

A hexadecimal number. Possibly gleaned from a hardware manual that says something like "The data register is at memory address 0xC000."

(unsigned char*)( 0xC000 )

A casting of that hexadecimal value to a pointer. It tells the compiler, "I realize it looks like I just made up this number, but I know what I'm doing and I really want you to treat it as a pointer to an unsigned character at the 0xC000 memory location."

*(unsigned char*)( 0xC000 )

A dereference of the resulting pointer. The unsigned character at memory location 0x2000.

#define LCD_DATA_REG (*(unsigned char*)( 0xC000 ))

You don't want to type that all the time, so you make a macro definition for it.

Now, you can do:

LCD_DATA_REG = value;

to write value to that memory location.

 

[Dawee1]

Thank you very much.