;FUNCTION NAME:CLEAR_EXTERNAL_DATA_MEMORY
     ;FUNCTION:CLEAR 4 BYTES EXTERNAL DATA MEMORY, ADDR INDEX BY DPTR
     ;
     CLEAR_EXTERNAL_DATA_MEMORY
           	MOV  	R2,#04H
           	CLR   	A
     $1   	MOVX   	@DPTR,A
           	INC   	DPTR
           	DJNZ   	R2,$1
           	RET
     ;