I'm using Internal Baud Rate Generator for UART,This is my code,but the pin TXD(At89s8252) can't move out any data!!! Why?

$INCLUDE (reg_c51.INC)

org 000h
ljmp begin

;/**
; * FUNCTION_PURPOSE: This file set up uart in mode 1 (8 bits uart) with
; * internal baud rate generator.
; * FUNCTION_INPUTS: void
; * FUNCTION_OUTPUTS: void
; */
org 0100h

begin:
MOV SCON,#40h; /* uart in mode 1 (8 bit), REN=0 */
ANL BDRCON,#0EEh; /* BRR=0; SRC=0; */
ORL BDRCON,#0Eh; /* TBCK=1;RBCK=1; SPD=1 */
MOV BRL,#0FDh; /* 9600 Bds at 11.059MHz */
SETB ES; /* Enable serial interrupt */
SETB EA; /* Enable global interrupt */
ORL BDRCON,#10h; /* Baud rate generator run*/

; * FUNCTION_OUTPUTS: P3.1(TXD) serial output
Again:
mov a,#10101010b
mov SBUF,a
ag:jnb ti,ag
clr ti
nop
nop
jmp Again

end