简单循环(读取温度-MC68HC) [英] Simple loop (reading temperature - MC68HC)

问题描述

我正在使用 MC68HC11 阅读与I/O相关的一章；这本书展示了一个建议的练习(不是很难的练习)，但是我无法通过使用汇编来解决它:

I was reading a chapter related to I/O using the MC68HC11; this book showed a suggested exercise (not really a hard one) but i was not able to solve it by using assembly:

我一直在思考，我可以通过使用一些基本逻辑来做到这一点(我使用C和C ++进行编程)，但是在尝试进行汇编时遇到了困难.

I've been thinking and i can do it by using some basic logic (i do program in C and C++ ) but i got stuck while trying to do it in assembly.

逻辑如下:

Loop:

value = ReadSensorValue()

if (value condition 1) // do action else if (value condition 2) // do something end if

go to Loop

可以帮助我解决问题，但要在汇编中使用真实的说明吗?

Can help me to solve it but using real instructions in assembly?

推荐答案

这是一种方法(使用 ASM11 ).我了解您正在尝试学习，但是您不付出任何努力. (这是我正在做的最后一个，没有先看到您的努力.)

Here's one way to do it (using ASM11). I understand you're trying to learn but you don't show any effort. (This is the last one I'm doing without seeing some effort from you first.)

;*******************************************************************************
; MCU specific
;*******************************************************************************

REGS                equ       $1000               ;register base
PORTB               equ       REGS+$04            ;port B (output only)
PORTC               equ       REGS+$03            ;port C
STACKTOP            equ       $01FF               ;Top of Stack
ROM                 equ       $F800               ;beginning of ROM
Vreset              equ       $FFFE               ;reset vector

;*******************************************************************************
; Application specific
;*******************************************************************************

TEMPERATURE         equ       PORTC               ;temperature is available here

CONTROL             equ       PORTB
HEATER.             equ       1                   ;bit that controls heater
COMPRESSOR.         equ       2                   ;bit that controls cooler

MIN_TEMP            equ       20                  ;min allowed temp in C
MAX_TEMP            equ       22                  ;max allowed temp in C

;*******************************************************************************
                    org       ROM
;*******************************************************************************

;*******************************************************************************
; Purpose: Get temperature as Centigrade degrees
; Input  : None
; Output : A = temperature in whole degrees (fractional part discarded)
; Note(s): Formula is TEMPERATURE*5/10 using integer arithmetic
;        : Simplifies to TEMPERATURE/2

GetTemperature      proc
                    ldaa      TEMPERATURE         ;A = temperature
                    lsra                          ;A = temperature/2
                    adca      #0                  ;(optional) round up
                    rts

;*******************************************************************************

CoolIt              proc
                    pshx
                    ldx       #CONTROL
                    bclr      ,x,HEATER.
                    bset      ,x,COMPRESSOR.
                    pulx
                    rts

;*******************************************************************************

HeatIt              proc
                    pshx
                    ldx       #CONTROL
                    bclr      ,x,COMPRESSOR.
                    bset      ,x,HEATER.
                    pulx
                    rts

;*******************************************************************************

AllOff              proc
                    pshx
                    ldx       #CONTROL
                    bclr      ,x,COMPRESSOR.|HEATER.
                    pulx
                    rts

;*******************************************************************************

Start               proc
                    lds       #STACKTOP
                    bsr       AllOff

Loop@@              bsr       GetTemperature      ;A = temperature in degrees

                    cmpa      #MIN_TEMP           ;if below minimum
                    blo       HeatIt@@            ; go heat it up

                    cmpa      #MAX_TEMP           ;if above maximum
                    bhi       CoolIt@@            ; go cool it down

                    bsr       AllOff              ;if within range turn all off
                    bra       Loop@@              ;go check temperature again

CoolIt@@            bsr       CoolIt
                    bra       Loop@@              ;go check temperature again

HeatIt@@            bsr       HeatIt
                    bra       Loop@@              ;go check temperature again

;*******************************************************************************
                    org       Vreset
                    dw        Start
;*******************************************************************************

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