whether The serial receive interrupt only occurs when RI is set due to some byte received, or the Timer1 causes it to execute according to the time set.
My code has a problem. pl. suggest what is wrong in this. actually when i don't use INC R0, code runs OK, and when I use INC R0 with all necessary switching of Banks, then also the ports over run. i don't underatand why R0 is getting over-run always as rest of the code is not using it in any way. Only Timer1 is used to have the SErial Receive. that's all.

Code goes here

All INTERRUPT LOCATIONS AND ORG DEFINED.

START:
PUSH PSW
PUSH A
SETB RS0
SETB RS1 ; BANK -3

MOV R0,#30H ; ADDRESS LOC.

POP A
POP PSW

WAIT: SJMP WAIT ; LOOP

RECEIVE:
CLR RI

PUSH PSW
PUSH A
SETB RS0
SETB RS1 ; BANK -3
INC R0

MOV @R0,SBUF
MOV P0,@R0 ;VALUE AT R0 IS
DISPLAYED
MOV P2,R0 ;ADDRESS OF R0 IS
DISPLAYED

POP A
POP PSW

RETI


pl. help.

PAWAN