Firstly, what the hell are you doing here??

mov A,#83h ;load register and set AUXR reg. (83h) to enable XRAM
mov R0,A ;size of 1792 bytes (max), XRAM is indirect
mov @R0,#10h ;AUXR = XRAM enabled, max size

The AUXR reg is 8Eh according to the atmel datasheet, 83h is DPH!

Also, you seem to be getting confused with indirection and accessing SFRs.

Your code should be something like:


AUXR .equ 8eh ;if your include file doesn't already have it

mov AUXR,#10h ;enable the xram



You should also make it easier on yourself if you write routines to dump the values out in hexadecimal through the serial port - makes reading the data a lot easier.

Also, you can make your code more straightforward by:

mov dptr,#abcd

or mov DPH,#12h

or mov DPH,#high ADDR
mov DPL,#low ADDR

Do a bit of reading on the instruction set - the 8051s are a little quirky when it comes to the different memory spaces. It takes a little time to get your head around it.