Here is example for one sec delay
make a loop to 10secs this works on timer one interrupt you may have modify the same.

; ****** FILE XAMPLE11.A51 *********************************
;
IE EQU 0A8H
ACC EQU 0E0H
PSW EQU 0D0H
TCON EQU 088H ; new : Timer/Counter Control
TMOD EQU 089H
TL0 EQU 08AH
TH0 EQU 08CH
; ; 250*100*40 microsec = 1 sec
T0valu EQU 25 ; 250 microsec for TIMER 0
TIME1 EQU 10 ; no. of loops for COUNT1
TIME2 EQU 40 ; no. of loops for COUNT2
;
ORG 050H ; via MONITOR RAM
COUNT1 DS 1 ; Software COUNTer 1
COUNT2 DS 1 ; COUNTer 2
POST DS 1 ; 1 means 1 sec has lapsed, else 0
;
ORG 4100H
START MOV DPTR,#INTT0 ; chain interrupt routine
MOV A,#2
MOV COMMAND,#ccLINK
LCALL MON
MOV TH0,#256-T0valu ; every 250 microseconds
MOV TL0,#256-T0valu ; one interrupt from TIMER0
MOV TMOD,#022H ; both COUNTers MODE2 2
MOV COUNT2,#TIME2 ; preset software COUNTer
MOV COUNT1,#TIME1
MOV POST,#0 ; no post
SETB TCON.4 ; start TIMER0
SETB IE.1 ; switch TIMER0 interrupt on
SETB IE.7 ; interrupts on
NEW MOV A,#'*' ; send asterisk
MOV COMMAND,#ccCHR
LCALL MON
WAIT MOV A,POST ; wait
JZ WAIT ; for POST
MOV POST,#0 ; get POST
SJMP NEW ; repeat
;
INTT0 PUSH PSW ; save
PUSH ACC
DJNZ COUNT1,IRET1 ; decrement software counter 1
MOV COUNT1,#TIME1 ; reload when 0 is reached
DJNZ COUNT2,IRET1 ; and decrement software counter 2
MOV COUNT2,#TIME2 ; reload when 0 is reached
MOV POST,#1 ; and leave POST
IRET1 POP ACC ; after storage
POP PSW
RETI ; end of interrupt
; MONITOR INTERFACE
COMMAND EQU 030H ; MONITOR command memory location
MON EQU 0200H ; MONITOR jump address
ccLINK EQU 040H ; Interrupt chaining
ccCHR EQU 001H ; send character
END