$MOD831
CSEG

ORG 0000h
	LJMP BEGIN
ORG 40h

BEGIN:
	MOV SCON,#50h
	MOV TMOD,#20h
	MOV TH1,#253
	SETB TR1

TEST:
	CLR TI
	MOV SBUF,#'a'
	JNB TI,$
	LJMP TEST