Hi Vasilis,

your example looks extreme unusual.
I can not see, what you want, since you ask about
the timer interrupt but there is no usage of it.

But if you only wait for receive, you can better use the polling
method without interrupt, e.g.:

main:

; ... do other initializations

clr es ;disable serial interrupt !
sjmp wait

receive:
mov p1, sbuf
mov p1, #10101010b ;I assume, you mean the value,
; not the address

wait: jbc ri receive ;Polling: wait for receive, then
; clear RI and serve it
sjmp wait



Regards,
Peter