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Appendix
C
Glossary
Introduction
Introduction
Since all the fields of man's activity are
regularly based on adequate and already adopted terms (through which
other notions and definitions become), so in the field of microcontrollers
we can single out some frequently used terms. Ideas are often connected so
that correct understanding of one notion is needed in order to get
acquainted with one or more of the other ideas.
Microcontroller
Microprocessor with peripherals in one electronic
component.
I/O
pin
External microcontroller's
connector pin which can be configured as input or output. In most cases
I/O pin enables a microcontroller to communicate, control or read
information.
Software
Information
that microcontroller needs in order to be able to function. Software can
not have any errors if we want the program and a device to function
properly. Software can be written in different languages such as: Basic,
C, pascal or assembler. Physically, that is a file on computer
disc.
Hardware
Microcontroller, memory, supply, signal circuits and all
components connected with microcontroller.
The other way of viewing
this (especially if it's not working) is, that, hardware is something you
can kick.
Simulator
Software
package for PC which simulates the internal function of microcontroller.
It is ideal for checking software routines and all the parts of the code
which do not have over demanding connections with an outside world.
Options are installed to watch the code, movement around the program back
and forth step by step, and debugging.
ICE
ICE (In Circuit Emulator), internal emulator, very useful
part of the equipment which connects a PC instead of microcontroller on a
device that is being developed. It enables software to function on the PC
computer, but to appear as if a real microcontroller exists in the device.
ICE enables you to move through program in real time, to see what is going
on in the microcontroller and how it communicates with an outside
world.
EPROM Emulator
EPROM
Emulator is a device which does not emulate the entire microcontroller
like ICE emulator, but it only emulates its memory. It is mostly used in
microcontrollers that have external memory. By using it we avoid constant
erasing and writing of EPROM memory.
Assembler
Software
package which translates source code into a code which microcontroller can
understand. It contains a section for discovering errors. This part is
used when we debug a program from errors made when program was
written.
HEX file
This is a file
made by assembler translator when translating a source file, and has a
form "understood" by microcontrollers. A continuation of the file is
usually File_name.HEX where the name HEX file comes from.
List file
This is a file made by assembler translator
and it contains all instructions from source file with addresses and
comments programmer has written. This is a very useful file for keeping
track of errors in the program. File extension is LST which is where its
name comes from.
Source File
File
written in the language understood by man and assembler translator. By
translating the source file, we get HEX and LIST
files.
Debugging
Error made in
writing a program, which error we are not aware of. Errors can be quite
simple such as typing errors, and quite complex such as incorrect use of
program language. Assembler will find most of these errors and report them
to '.LST' file. Other errors will need to be searched for by trying it out
and watching how device functions.
ROM,
EPROM, EEPROM, FLASH, RAM
Types of memories we meet with microcontroller use. First
one can not be erased, what you write in it once, stays forever, and can
not be erased. The second is erasable with UV lamp. Third one can be
erased electrically, using voltage which microcontroller operates on.
Fourth one is electrically erasable, but unlike EEPROM memory it does not
have such a great number of cycles of writing and erasing at memory
locations. Fifth one is fast, but it does not hold back the contents as
the previous when there is supply shortage. Thus, program is not stored in
it, but it serves for different variables and
inter-results.
Addressing
Determines
and designates certain memory locations.
ASCII
Short for "American Standard Code for Information
Interchange". It is widely accepted type of coding where each number and
letter have their eight-bit code.
Carry
Transfer bit connected with arithmetic
operations
Code
File, or section
of a file which contains program instructions.
Byte, Kilobyte,
Megabyte
Terms designating
amounts of information. The basic unit is a byte, and it has 8 bits.
Kilobyte has 1024 bytes, and mega byte has 1024
kilobytes.
Flag
Bits from a status
register. By their activation, programmer is informed about certain
actions. Program activates its response if
necessary.
Interrupt
vector or interrupts
Location
in microcontroller memory. Microcontroller takes from this location
information about a section of the program that is to be executed as an
answer to some event of interest to programmer and
device.
Programmer
Device which
makes it possible to write software in microcontroller memory, thus
enabling the microcontroller to work independently. It consists of the
hardware section usually connected with one of the ports and software
section used on the computer as a program.
Product
Product development is a combination of luck
and experience. Short terms, or time-limits for production should be
avoided because even with most simple assignments, much time is needed to
develop and improve. When creating a project, we need time, quiet, logical
mind and most importantly, a thorough understanding of consumer's needs.
Typical course in creating a product would have the following
algorithm.
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