汇编怎么实现定时器和主程序同时进行呢？

Question

主程序在进行数码管的刷新扫描。
然后定时器同时进行，定时器时间一到，就中断主程序进行数码管的数值刷新

Answer 1

   ORG     00H
    JMP     CHENGXU
    ORG     14H
    JMP     ISR_STM

CHENGXU:
CLR SCAN_PORTC
CLR SCAN1_PORTC
MOV A,10101000B
MOV WDTC,A
MOV A,00100000B
MOV TM2C0,A
MOV A,11000000B
MOV TM2C1,A
MOV A,LOW 1000
MOV TM2AL,A
MOV A,HIGH 1000
MOV TM2AH,A
SET T0ON
SET EMI
SET MF0E
SET T2AE
CLR T2AF
MOV A,00010000B
MOV SCAN,A
MOV SCAN_PORT,A
CLR SEG_PORTC

    MOV     A,OFFSET TAB_7_SEG
    MOV     TBLP,A
    MOV     A,10
    MOV     COUNT,A
    MOV     COUNT1,A

RE_START:
CLR DIGIT[0]
CLR DIGIT[1]

LOOP:
MOV A,OFFSET TAB_7_SEG
MOV TBLP,A
MOV A,DIGIT[0]
ADDM A,TBLP
TABRDL SEG_PORT
MOV A,00010000B
MOV SCAN,A
MOV SCAN_PORT,A
MOV A,1
CALL DELAY1
CLR SCAN_PORT

LOOP1:
MOV A,OFFSET TAB_7_SEG
MOV TBLP,A
MOV A,DIGIT[1]
ADDM A,TBLP
TABRDL SEG_PORT
MOV A,00000001B
MOV SCAN1,A
MOV SCAN1_PORT,A
MOV A,1
CALL DELAY1
CLR SCAN1_PORT
JMP LOOP

ISR_STM:
MOV STACK_A,A
MOV A,STATUS
MOV STACK_STATUS,A
INC DIGIT[0]

    SDZ    COUNT1
    JMP    $+5
    CLR    DIGIT[0]
    INC    DIGIT[1]
    SDZ    COUNT 
    JMP    $+1    
      MOV    A,STACK_STATUS
   MOV    STATUS,A
    MOV    A,STACK_A
    RETI 

这是我的代码，有没有大佬看看哪里出错了呢？好像不能跳转到中断子程序