Debugger uvision5 failure when accessing an externally declared variable

Hi all,

I am stuck onto a rare problem that I try to expose next.

First, I got somewhere within the code the variable W_dp_0 declared like:

extern unsigned char    W_dp_0;

W_dp_0 is actually initialized inside a library into which I don't have access at all.

Now I show you the beginning code of function Compose_Prot(), the last line of which is the one that's causing the problem:

void Compose_Prot (void){
  bool is_valid = FALSE;
  char val[7];
  char st1, st2, st3;
  unsigned char j = (unsigned char) W_dp_0;

At the disassembler window I have the lines shown next, that correspond to the assignment to j:

0x080006BA 4882      LDR      r0,[pc,#520]  ; @0x080008C4
0x080006BC 7805      LDRB     r5,[r0,#0x00]

The memory map is like:

0x080008c4  C7 01 00 20
0x080008c8  13  01 00 20

and at the address of W_dp_0:

0x200001c6 02 03 04 01
0x200001ca 00 00 0A 00

So that after the execution, R0 is

0x200001C7

and R5, which corresponds to j variable:

0x00000003

But, if I now print values of variables in the command window I see that:

> W_dp_0
0x01040302
> &W_dp_0
0x200001C6
> (unsigned char) W_dp_0;
0x02
> j
0x03

So why j equals 0x03 and not 0x02 as expected and agreed to the Command Window?
What else can I do to find any clue that helps me find a reason?
And finally, why the disassembler computes the address 0x080008C4, instead of 0x80008c2 that would correspond to the addition of PC + 520 ( 0x080006ba + 520 ) ?

Thanks in advance,

Carles