Файл: Microcontroller Programming. Thi Micro Chip PIC (Julio Sanchez, 2007).pdf

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; Configuration Bits

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Names in the include file are defined in all-capital letters. It is probably a good idea to adhere to this style instead of creating alternate names in lower case. The C-like #include directive is used to refer the .inc files at assembly time, for example:

#include <p16f84a.inc>

9.4.6 Errorlevel Directive

This directive allows controlling the warning and error messages produced at assembly and link times. One particular type of warning can be disturbing: those that refer to bank changes. Applications often turn off bank change related warning with the following line:

errorlevel -302

9.5 Pseudo Instructions

Sometimes a code listing contains instructions that are not part of the standard set for the particular device. The reason this happens is that MPLAB includes a set of p s e u d o - i n s t r u c t i o n s f o r 1 2 - a n d 1 4 - b i t d e v i c e s . Ta b l e 9 . 2 l i s t s t h e s e pseudo-instructions and their standard equivalents:

Table 9.2

PIC Pseudo Instructions

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Chapter 10

Programming Essentials: Input and Output

In this chapter, we discuss the simplest circuits and programming operations. Using a PIC to control an LED or read a switch is as elementary as it gets. However, neither of these operations is trivial, since there is more to it than a few lines of code. Other input/output devices that are also considered are seven-segment LED displays and multiple switches, sometimes called toggle switches. A bank of multiple LEDs can also function as a binary output device.

10.0 16F84A Programming Template

We have found that program development can be simplified considerably by using code templates. A code template is a program devoid of functionality that serves to implement the most common and typical features of an application. The template not only saves the effort of redoing the same tasks, but reminds the programmer of program elements that could otherwise be forgotten. A professional developer will have collected many different templates over the years for different types of applications on various processors. The following template is for the 16F84A PIC:

;============================================================

;File name:

;Date:

;Author:

;Processor:

;Reference circuit: ;============================================================

;Copyright notice: ;============================================================

;Program Description:

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;configuration switches ;===========================

;Switches used in __config directive:

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