Hello all, I've run into another weird problem that doesn't make sense.

;INT0--- keyboard interrupt
;TF0----timer0 interrupt

main:

MOV A, NBYTES ;if nbytes=1, key was pressed
JZ MYLOOP

MOV IE, #00H
MOV A, KEYBUFF ;get keycode
MOV NBYTES, #00H
MOV R1, RX_POSITION;save it into buffer
MOV @R1, A
INC R1
MOV RX_POSITION,R1
MOV IE, #81H

;i thought timer0 has a lower priority than INT0, when the time between two keys pressed is much shorter than timer period.. I think the program will wait at here, but it didn't, what's the problem? In my ISR, i reset the TH0 and TL0,but still not work..

MOV TH0,#11 ;50ms timer
MOV TL0,#220
MOV TMOD,#01
SETB TR0
JNB TF0,$ ;I thought program will wait here until timer overflow. I reset the TH0 and TL0 in my ISR, is it real help?



MOV R3, #00
MOV R2, RX_POSITION
MOV R0, #RX_BUFFER
MOV R1, #TX_BUFFER

MYLOOP1:
MOV A, @R0
MOV @R1, A
INC R1
INC R0
DEC R2
INC R3
CJNE R2, #RX_BUFFER, MYLOOP1

MYLOOP:

RET

Regards


Frank