8085 微处理器模拟秒表的程序

我们编写了一个 8085 汇编语言程序，仅仅是为了模拟一个秒表，以便在地址字段中显示分钟和秒。还提供了一个暂停秒表的功能，以及继续显示在停止命令之前的时间的显示。

FILE NAME STOPWACH.ASM
PRESSING THE ‘VECT INTR’ KEY STOPS THE STOPWATCH, WITH STATIONARY DISPLAY
ORG C000H
CURAD: EQU FFF7H
UPDAD: EQU 06BCH

RESET: LXI H,0000H
REPEAT: SHLD CURAD
CALL UPDAD; Display time present in HL in the address field
MVI A, 00011011B
SIM ; Unmask RST7.5, Reset RST7.5 flip flop
EI ; Enable interrupt system

CALL DELAY ; Generate a delay of 1 second

LHLD CURAD
MOV A, L
ADI 01H
DAA ; Increment L value in decimal
CPI 60H
JZ INC_MIN ; If L = 60, jump to INC_MIN

MOV L, A
JMP REPEAT

INC_MIN:

MVI L, 00H
MOV A, H
ADI 01H
DAA ; Make L = 0, and increment H in decimal
CPI 60H
JZ RESET ; If H = 60, jump to RESET

MOV H, A
JMP REPEAT

; Subroutine to generate a delay of 1 second

; To check the proper working of minutes display, load DE with
; 0444H in this subroutine instead of FFFFH. Then the minutes’ display
; will change every second, so that we can test the proper working in
; 60 seconds, instead of waiting for 60 minutes.

DELAY: MVI B, 02H
OUTLOOP: LXI D, FFFFH

INLOOP: DCX D
MOV A, D
ORA E
JNZ INLOOP

DCR B
JNZ OUTLOOP
RET

RST7.5 Interrupt Service Subroutine

ORG FFB1H ; For ESA Kit it should be ‘ORG 8FBFH’
HLT ; ; This is the RST7.5 ISS

更新于：2019 年 7 月 30 日

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