SW006010 Microchip Technology, SW006010 Datasheet - Page 21

• Manufacturer Part Number: SW006010
• Description: MPLAB 17C SOFTWARE
• Manufacturer: Microchip Technology

Specifications of SW006010

• Tool Function: Compiler
• Tool Type: Compiler
• Processor Series: PIC17C
• Lead Free Status / RoHS Status: Not applicable / Not applicable
• For Use With/related Products: MPLAB®
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

2.1
2.2
2.3
 2002 Microchip Technology Inc.
Chapter 2. Differences Between MPLAB C17 and ANSI C
INTRODUCTION
HIGHLIGHTS
MPLAB C17 vs. ANSI C
This chapter discusses the differences between MPLAB C17 and ANSI C.
Items discussed in this chapter are:
• MPLAB C17 vs. ANSI C
• Components of a Basic MPLAB C17 Program
• Keyword Differences
• Statement Differences
• Oddities of Standard Functions
Most C programmers have gained their experience programming C on computers
where there was an operating system to handle such things as memory management,
input/output, interdevice communications, etc. Microcontrollers, by their very nature,
do not have the memory overhead for an operating system. Therefore, the compiler
expects the user to implement memory allocation, I/O operation through a peripheral,
and other specialized tasks. Libraries and precompiled object files are available with
MPLAB C17 to aid the programmer in this endeavor.
An MPLAB C17 program is a collection of declarations, statements, comments and
preprocessor directives that typically do the following:
• Declare data structures
• Allocate data space
• Evaluate expressions
• Perform program control operations
• Control PICmicro MCU peripherals
Additionally, after source code is compiled, it must be programmed into a device. In
the device environment, RAM is in an undefined state on power-up. The program
must take care of initializing any variables that are set in the code. This is
accomplished by storing the variable values in program memory and then moving
them to RAM before the
pre-execution items that may be necessary, such as setting up a software stack.
These specialized items may be written in C or assembly code. In either case, the
programmer must decide what is needed.
main()
function executes. There are other
MPLAB
®
C17 C COMPILER
USER’S GUIDE
main()
apRNOVM^-page 15
Part
Part
Part
Part
1
2
3
4