Here is the timing loop from my packet driver. It should last 1ms.
XTAL EQU 11059 ;THE XTAL SPEED FOR YOUR 8052, MHZ/1000
ITEMP_F DATA 7FH

LONGPAUSE: ; this should hold out for ~1ms,
TEMP SET XTAL / 12
TEMP SET TEMP / 8
MOV ITEMP_F,TEMP
LONGPAUSE_0: SWAP A
SWAP A
SWAP A
SWAP A
DJNZ ITEMP_F,LONGPAUSE_0
RET