prog45.asm

主要是8051源代码

;  PROG45 - Poll a button and turn on an LED
;
;  This Application Turns on an LED and Loops forever afterward.
;
;  Myke Predko
;  98.02.18
;
;  Hardware Notes:
;  80C520 Running at 1 MHz
;  P1.0 is the LED (to light, it is pulled down)
;  P1.1 is connected to a Momentary ON Switch that Pulls down the Line.

;  Variable Declarations

;  Mainline
 org 0                          ;  Execution Starts Here

Loop:                           ;  Loop Here Forever

  jb     P1.1,LEDON             ;  If Button High, Make LED High

  anl    P1,#0FEh               ;  Pull Down P1.0 To Turn on LED

  ajmp   Loop

LEDON:                          ;  Button High, Turn On LED

  orl    P1,#001h

  ajmp   Loop