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EE ME

FR LE

EPE PIC

TUTORIAL V2

JOHN BECKER

PART ONE

WHAT IT’S ALL ABOUT

the time that the original

EPE PIC Tutorial

was published in March to

May 1998, letters and phone calls to

EPE

had been showing that interest

in Microchip’s PIC microcontrollers had become intense.

Many readers were asking for more information on how to use

these devices in designs of their own invention.

In the words of one reader, “I find the PIC data sheets

too skimping on everyday detail, and the published

software too complex. Please show me how to get to

grips with the

essence

of PICs. Tell me, step-by-

step, how to get started with writing simple

programs, how to just turn on a single light

emitting diode, for example. Then take me

forward from there.”

It was to meet this demand that the original

EPE PIC Tutorial

was published. Its success

resulted in a CD-ROM version being produced

commercially as

PICtutor,

complete with its own

ready-built development board. Recently that

version was upgraded to become

Assembly for

PICmicro V2

along with its Version 2 PICmicro MCU

board (see elsewhere in

EPE

for details). Many thousands

of people have learned to program PICs through these

several versions.

However, we frequently receive requests from readers for PIC

programming education that is available at minimal cost. The

aim of this three-part

EPE PIC Tutorial V2

series is to

do just that, as detailed more fully on the next

two pages. In a nutshell, though, it gets

you inexpensively started with

PICs, and does so

“step-by-step”.

Quite

simply

the easiest

low-cost

way to learn

about using

PIC

Microcontrollers!

EPE PIC

TUTORIAL V2

01202 873872

PIC TOOLKIT TK3

AND ITS VERSATILE

BOARD SHOW YOU HOW!

Everyday Practical Electronics, April 2003

PIC Tutorial V2 Supplement

–

THIS REVISION

Over five years on from the publication

of the original

EPE PIC Tutorial,

a number

of things have changed, yet at the same

time the basics of programming PIC

microcontrollers have not.

This revision is thus a mixture of the old

and the new. The old aspect is that the com-

mands used to program PICs remain the

same. The new aspects, though, are several:

The original

EPE PIC Tutorial

illustrat-

ed its example programs in a programming

dialect known as TASM. This dialect is

usable with a variety of tables whose con-

tents can be modified to suit many types of

microcontroller and microprocessor. It had

been modified to suit PICs by reader

Darren Crome.

This revision now has its programming

examples written in Microchip’s own PIC

programming dialect, MPASM. This dialect

is the “industry standard” and thus has far

wider appeal than TASM, although the basic

differences between the two are slight.

Secondly, the original

EPE PIC Tutorial

concentrated on the now-obsolete

PIC16C84 as being the target device. This

microcontroller effectively became replaced

in 1997 by the pin-for-pin compatible

PIC16F84, which is an equally excellent

device to use to illustrate PIC programming

techniques. More recently the PIC16F84A

has arrived on the scene. The PIC16F84 and

PIC16F84A (two of the devices in the

PIC16F8x family) can be used interchange-

ably in this

EPE PIC Tutorial V2

(referred

to from now on as the

Tutorial).

RESOURCES

A special composite

EPE PIC

Resources CD-ROM

has been produced

to accompany this series. It includes the

Tutorial

software for the entire series,

EPE Toolkit TK3

software, complete

reproductions of the

TK3

texts of

Oct/Nov ’01,

Using TK3 with Windows

XP and 2000

(Oct ’02) and a broad selec-

tion of PIC-related articles published in

EPE

over the last several years and

which illustrate practical examples of

various advanced programming func-

tions and techniques. Some unpublished

articles are included as well. The full list

is given elsewhere in

EPE.

Alternatively, software for

TK3

and

this

Tutorial

can be downloaded

free

from

the

EPE

FTP Site. Disks for both sets of

software (CD-ROM for

TK3,

and 3.5in

disk for this

Tutorial)

are also available

are included on the

EPE PIC Resources

CD-ROM.

From hereon the software and

p.c.b. are jointly referred to simply as

TK3.

It should be noted that

TK3

was written

to run under Windows 95, 98 and ME. To

run it under Windows NT, XP and 2000 the

software must be used as described in

Mark Jones’ article

Using TK3 with

Windows XP and 2000

of Oct ’02. This

article is also carried on the

EPE PIC

Resources CD-ROM.

In keeping with the original

Tutorial,

assume in this series that you have no pre-

vious knowledge of PICs and their pro-

gramming. We thus start as we did before,

by explaining the basic nature of a PIC

microcontroller.

from the

EPE

Editorial Office. Back

issues (or photocopies) or Back Issue

CD-ROMs of published texts can also be

purchased (see the

Back Issues

page).

The

EPE

FTP Site is most easily

accessed via the main page at

www.epemag.wimborne.co.uk.

Click

on the

FTP Site (Downloads)

option at

the top, then click down the paths

pub/PICS

then select

PIC Tutorial V2

Toolkit TK3.

The printed circuit board for

TK3

available from the

EPE PCB Service,

code 319. Note, you will require the

relevant back issues or the

EPE PIC

Resources CD-ROM

to be able too build

this.

See the

EPE PCB Service

page for the

price and ordering details of the disks

and p.c.b.

RA2

RA3

RA4/TOCKI

MCLR

GND

RB0/INT

RB1

RB2

RB3

RA1

RA0

OSC1/CLK IN

OSC2/CLK OUT

RB7

RB6

RB5

RB4

FAMILY MATTERS

Once you know how to program a

PIC16F84 you are well equipped to write

programs for other PICs, although there are

some minor differences in the way that the

various PIC families handle some of the

same functions.

Apart from the PIC16F8x family, two

other PIC families are eminently suited to

hobbyist constructors, notably the

PIC16F87x and PIC16F62x families

(although they are not immediately suited

to this

Tutorial).

However, in the final part

of this three part series, basic differences

between the way that the PIC16F8x,

PIC16F87x and PIC16F62x families do the

same thing are highlighted and the Tutorial

programs can be readily modified to run on

these devices. Examples of some useful

routines specific to the PIC16F87x family

are included.

It is stressed, though that this

Tutorial

does not attempt to be a full tutorial on

every aspect of the three families. Nor does

it examine specific aspects of some other

PIC families whose functions are more

advanced than most readers probably

require.

Also, the

Tutorial

does not teach the use

of Microchip’s MPASM and MPLAB pro-

gramming software, and it does not cover

any PIC variant or dialect that is pro-

grammed in versions of BASIC.

An important aspect of this revision is

that it has been designed for use with the

EPE PIC Toolkit TK3

printed circuit board

and software (published Oct/Nov 2001),

both of which, plus their two texts, you

need in order to get full benefit from this

Tutorial.

See the Resources panel for

details of obtaining them. Note that these

WHAT IS A PIC?

Fig.1. Pinouts for the PIC16F8x family.

by Microchip. When asked about the name’s

origin, Microchip’s Technical Department

A PIC chip, in this context, is a micro-

controller integrated circuit manufactured

BASIC PIC16F84 SPECIFICATIONS

35 single-word commands (see

Table 1)

1K × 14-bit EEPROM program

memory

68 × 8-bit general purpose SRAM

registers

15 special function hardware registers

(see Table 2 later)

64 × 8-bit EEPROM data memory

1000 program memory erase/write

cycles (typical)

10,000,000 data memory erase/write

cycles (typical)

Data retention >40 years

5 data input/output pins, Port A

8 data input/output pins, Port B

25mA current sink maximum per pin

20mA current source maximum per

80mA maximum current sunk by

Port A

50mA maximum current sourced by

Port A

150mA maximum current sunk by

Port B

100mA maximum current sourced by

Port B

Total power dissipation 800mW

8-bit timer/counter with 8-bit

prescaler

Power-on reset (POR)

Power-up timer (PWRT)

Oscillator start-up timer (OST)

Watchdog timer (WDT) with own

on-chip RC oscillator

Power saving Sleep function

Code protection

Serial in-system programming

Selectable oscillator options:

RC: low cost RC oscillator

XT: standard crystal/resonator

(100kHz to 4MHz)

HS: high speed crystal/resonator

(4MHz to 10MHz) (to 20MHz for

’F84A)

LP: power-saving low frequency

crystal (32kHz to 200kHz)

Interrupts:

External, RB0/INT pin

TMR0 timer overflow

Port B RB4 to RB7 interrupt on

change

Data EEPROM write complete

Operating voltage range: 2·0V to

6·0V (to 5·5V for ’F84A)

Power consumption:

<2mA @ 5V, 4MHz

15mA typical @ 2V, 32kHz

<1mA typical standby @ 2V

– PIC Tutorial V2 Supplement

Everyday Practical Electronics, April 2003

TUTORIAL CONCEPTS EXAMINED

TUTORIAL 1:

Minimum commands needed

Port default values

Instruction ORG

Instruction END

Command GOTO

Program TK3TUT1.ASM

TUTORIAL 2:

Clock cycles

File registers

Bits

Bytes

Set

Clear

Command CLRF

Command CLRW

Command BSF

Command BCF

Ports and Port directions

STATUS register bit 5

Banks 0 and 1

Program TK3TUT2.ASM

TUTORIAL 3:

Names in place of numbers

Case sensitivity

Labels

Repetitive loop

Instruction EQU

Program TK3TUT3.ASM

TUTORIAL 4:

Command MOVLW

Command MOVWF

Command RLF

Command RRF

Command BTFSS

Command BTFSC

Instruction #DEFINE

Instruction BANK0

Instruction BANK1

Naming numbers

Bit naming

Program counter

STATUS register bit 0

Carry flag

Bit codes C, F, W

Bit testing

Conditional loop

Pin protection

Program TK3TUT4.ASM

Program TK3TUT5.ASM

TUTORIAL 5:

STATUS bit 2

Zero flag

Bit code Z

Command MOVF

Program TK3TUT6.ASM

TUTORIAL 6:

Command INCF

Command DECF

Command INCFSZ

Command DECFSZ

Counting upwards

(incrementing)

Counting downwards

(decrementing)

Use of a file as a counter

Program TK3TUT7.ASM

TUTORIAL 7:

Switch monitoring

Command ANDLW

Command ANDWF

Command ADDWF

Command ADDLW

Nibbles

STATUS bit 1

Digit Carry flag

Bit code DC

Program TK3TUT8.ASM

TUTORIAL 8:

Increasing speed of

TK3TUT8

Bit testing for switch status

Program TK3TUT9.ASM

TUTORIAL 9:

Responding to a switch press

only at the moment of

pressing

Program TK3TUT10.ASM

TUTORIAL 10:

Performing functions

dependent upon which switch

is pressed

Use of a common routine

serving two functions

Program TK3TUT11.ASM

TUTORIAL 11:

Reflecting PORTA’s switches

on PORTB’s l.e.d.s

Command COMF

Command SWAPF

Inverting a byte’s bit logic

Swapping a byte’s nibbles

Program TK3TUT12.ASM

Program TK3TUT13.ASM

Program TK3TUT14.ASM

TUTORIAL 12:

Generating an output

frequency in response to a

switch press

The use of two port bits set

to different input/output

modes

Command NOP

Program TK3TUT15.ASM

TUTORIAL 13:

Command CALL

Command RETURN

Command RETLW

Program TK3TUT16.ASM

TUTORIAL 14:

Tables

Program TK3TUT17.ASM

TUTORIAL 15:

Using four switches to create

four different notes

Use of a table to selectively

route program flow

Program TK3TUT18.ASM

TUTORIAL 16:

Indirect addressing

Using unnamed file

locations

Program TK3TUT19.ASM

TUTORIAL 17:

Tone modulation

Command XORLW

Command XORWF

Command IORLW

Command IORWF

Program TK3TUT20.ASM

Program TK3TUT21.ASM

Program TK3TUT22.ASM

TUTORIAL 18:

Use of internal timer

Program TK3TUT23.ASM

TUTORIAL 19:

BCD (Binary Coded

Decimal) counting

Program TK3TUT24.ASM

TUTORIAL 20:

Real-time timing at 1/25th

second

Counting seconds 0 to 60

Program TK3TUT25.ASM

TUTORIAL 21:

Using 7-segment l.e.d.

displays

Showing hours, minutes and

seconds

Command IORLW (usage)

Program TK3TUT26.ASM

Program TK3TUT27.ASM

Program TK3TUT28.ASM

TUTORIAL 22:

Using intelligent l.c.d.s

Setting l.c.d. contrast

Initialising the l.c.d.

Sending a message to the

l.c.d.

Program TK3TUT29.ASM

TUTORIAL 23:

Coding hours, minutes and

seconds for an l.c.d.

Shortened clock monitoring

code

Command SUBLW

Command SUBWF

Program TK3TUT30.ASM

TUTORIAL 24:

Adding time-setting switches

Program TK3TUT31.ASM

TUTORIAL 25:

Writing and reading

EEPROM file data

Program TK3TUT32.ASM

TUTORIAL 26:

Illustrating use of EEPROM

data read/write

Converting binary value to

hexadecimal

Program TK3TUT33.ASM

TUTORIAL 27:

Interrupts

Command RETFIE

Program TK3TUT34.ASM

Program TK3TUT35.ASM

TUTORIAL 28:

Command SLEEP

Program TK3TUT36.ASM

TUTORIAL 29:

Watchdog timer (WDT)

Command CLRWDT

Program TK3TUT37.ASM

TUTORIAL 30:

Misc Special Register bits

TUTORIAL 31:

INCLUDE files command

Embedded configuration data

Embedded Data EEPROM values

Embedded PIC type data

Embedded Radix

Program TK3TUT38.ASM

TUTORIAL 32:

PIC16F8x, PIC16F87x,

PIC16F62x family coding

differences

PIC16F87x PORTA

PIC16F87x Data EEPROM use

PIC16F62x PORTA

PIC16F62x Data EEPROM use

Program TK3TUT39.ASM

Program TK3TUT40.ASM

TUTORIAL 33:

Converting binary values to

decimal

Program TK3TUT41.ASM

TUTORIAL 34:

Multiplication routine

Program TK3TUT42.ASM

TUTORIAL 35:

Division routine

Program TK3TUT43.ASM

TUTORIAL 36:

ADC conversion routine for

PIC16F87x family

Program TK3TUT44.ASM

TUTORIAL 37:

CBLOCK command

Interfacing to external serial

EEPROM chips, for PIC16F87x

family

Program TK3TUT45.ASM

TUTORIAL 38:

Outputting serial data at a

specified BAUD rate, for

PIC16F87x family

Program TK3TUT46.ASM

TUTORIAL 39:

Practical example recording

analogue data to serial

EEPROM and subsequent

outputting as RS-232 serial data

Program TK3TUT47.ASM

TUTORIAL 40:

Programming

PICs vs. hardware

Summing-up

APPENDIX A:

Bugged Teaser!

APPENDIX B:

Useful PIC information

Further reading

Everyday Practical Electronics, April 2003

PIC Tutorial V2 Supplement

–

replied,

“PIC is not an acronym; it is just a

trademarked

name

that

General

Instruments came up with a long time ago”.

(GI were the originators of PICs.)

A microcontroller is similar to a micro-

processor but it additionally contains its

own program command code memory, data

storage memory, bi-directional (input/out-

put) ports and a clock oscillator. Many

microprocessors require the use of addi-

tional chips to provide these requirements;

microcontrollers are totally self-contained.

The great advantage of microcontrollers is

that they can be programmed to perform

many functions for which many other chips

would normally be required. This not only

makes for simplicity in electronic designs,

but also allows some functions to be per-

formed which could not be done using nor-

mal digital logic chips – i.e. circuits for

which, previously, a microprocessor and

peripheral devices would have been required.

PICs are manufactured and supplied

“empty”. That is, they are without program

codes (commands) and cannot control a

circuit until they have been provided with a

program that tells them what to do. It is the

task of the program writer (you) to tell

them what that is.

The commands are written in a spe-

cialised form of English, largely consisting

of mnemonics, known as the “source

code”. An assembly program (such as

TK3)

then translates (assembles) the source code

commands into a numerical form that the

PIC can understand, the “program code”.

This code, which is normally in hexadeci-

mal, is then sent (loaded) in binary format

to the PIC by electronic hardware, such as

TK3’s

p.c.b.

TABLE 1. PIC COMMAND CODES FOR PIC16F8x, PIC16F87x

AND PIC16F62x

Command/Syntax

Flags

affected

Cycles

Description

Tutorial

discussed

17, 21

BYTE-ORIENTATED FILE REGISTER OPERATIONS

ADDWF

f,d

C, DC, Z

Add W and f

ANDWF

f,d

AND W with f

CLRF

Clear f

CLRW

–

Clear W

COMF

f,d

Complement f

DECF

f,d

Decrement f

DECFSZ

f,d

–

1 (2)

Decrement f, skip if 0

INCF

f,d

Increment f

INCFSZ

f,d

–

1 (2)

Increment f, skip if 0

IORWF

f,d

Inclusive OR W with f

MOVF

f,d

Move f

MOVWF

–

Move W to f

NOP

–

No operation

RLF

f,d

Rotate left f through Carry

RRF

f,d

Rotate right f through Carry

SUBWF

f,d

C, DC, Z

Subtract W from f

SWAPF

f,d

–

Swap nibbles in f

XORWF

f,d

Exclusive OR W with f

BIT-ORIENTATED REGISTER OPERATIONS

BCF

f,b

–

BSF

f,b

–

BTFSC

f,b

–

1 (2)

BTFSS

f,b

–

1 (2)

LITERAL AND

ADDLW

ANDLW

CALL

CLRWDT

GOTO

IORLW

MOVLW

RETFIE

RETLW

RETURN

SLEEP

SUBLW

XORLW

CONTROL OPERATIONS

C, DC, Z

–

TO, PD

–

TO, PD

C, DC, Z

Bit

clear f

set f

test f, skip if 0

test f, skip if 1

PIC VARIETIES

There are many families of PIC micro-

controller available, ranging from those

which can only be programmed once, to

those that can be repeatedly repro-

grammed. The former are typically known

as One Time Programmable (OTP)

devices, and because of this characteristic

are not well-suited to hobbyist use since

they cannot have their software code

changed once they have been programmed.

There are two basic families of repro-

grammable PICs: those that require an

ultra-violet light unit to erase their previous

data before being reprogrammed, but

which are now essentially obsolete, and

those which are electrically erasable.

In the latter category fall the three device

families already mentioned, of which it is

the PIC16F84 device we use here. It has

been chosen because of its ease of repro-

gramming and because it does not have

additional features that can prove difficult

to understand for beginners. Its pinouts are

shown in Fig.1, and its basic attributes

given in the Specifications panel.

It is an EEPROM (electrically erasable

programmable read only memory) device,

also known as a “Flash” device, hence the

“F” infix in its type number. This means

that it can be rapidly reprogrammed as

often as you wish, without the need for

ultra-violet erasing.

Add literal and W

AND literal with W

Call subroutine

Clear Watchdog Timer

Go to address

Inclusive OR literal with W

Move literal to W

Return from interrupt

Return with literal in W

Return from subroutine

Go into standby mode

Subtract W from literal

Exclusive OR literal with W

chip can be used: 4MHz, 10MHz and

20MHz respectively. You may use any

device speed rating for this

Tutorial,

although the -04 is likely to be stocked by

more component suppliers.

The PIC16F84 used here has two

input/output (I/O) ports, Port A and Port B.

Port A has five pins (RA0 to RA4), and

Port B has eight pins (RB0 to RB7). We

shall be using the PIC in two of its four

oscillator modes, RC (resistor/capacitor)

and XT (standard crystal up to 4MHz), the

former being variable, the latter using a

3·2768MHz crystal.

To re-emphasise an earlier point, much

of the information about the commands

which we present here is, in most

instances, applicable to other members of

the PIC family. Once you understand a

PIC16F84 you should have no difficulty

applying your knowledge to other PICs.

suitable power supply (TK3 runs from

9V d.c., which can be supplied via a

plug-in mains adaptor)

word-processing program (text editor)

assembly and send (download) software

program (e.g.

TK3)

It is worth noting that this

Tutorial

and

the

TK3

software can be used with

Magenta’s version of the

TK3

board, and

with the commercial Version 2 PICmicro

MCU Development Board. However, these

two boards do not have the numbered CP

connection points referred to in this text

regarding the

EPE TK3

board, but they do

have pin function notations and the con-

nections should be obvious.

Data is output from the computer to the

PIC via the parallel printer port (addresses

378h, 278h and 3BCh are supported by

TK3).

It is output serially, data on port line

D0, and a clock signal on line D1.

Additional computer printer port lines are

used by

TK3

to enable such functions as

reading back program code from a PIC.

You must be able to use a word-process-

ing program. This must produce a text file

that is totally without formatting and printer

commands. That is, it must be able to gen-

erate a pure ASCII text file (and to input

one). It is stressed that the source code

(.ASM) files

must

be in pure ASCII text

formats without printer or display format

WHAT YOU NEED

There are six things that you need in

order to program a PIC:

PC-compatible computer having a stan-

dard (Centronics-compatible) parallel

printer port (USB ports are not suitable)

purpose built programming hardware

board (e.g.

TK3)

standard (Centronics) parallel printer

port connecting cable

SUB-VERSIONS

Note that there are several sub-versions

of individual PIC types, having suffixes

such as -04, -10 and -20. The suffix indi-

cates the maximum clock rate at which the

– PIC Tutorial V2 Supplement

Everyday Practical Electronics, April 2003

commands embedded in them. (TK3 offers a

choice of editors, including DOS Edit,

Windows Notepad and Windows Wordpad.)

ADDITIONAL

COMPONENTS

To use this

Tutorial

with the basic

TK3

p.c.b. you need the following additional

components:

330W resistor, 0·25W 5% carbon film (8

off)

1mF capacitor, axial elect. 10V

2-line, 16-characters per line alphanu-

meric liquid crystal display module and

datasheet

Optional: 4-digit multiplexed common

cathode 7-segment l.e.d. display module

and datasheet

Personal (high-impedance) headphones

Jack socket to suit headphones

Extra push-to-make switch for connec-

tion via flying leads

Stranded connecting wire

Solder

ANOTHER NEED

Throughout this

Tutorial

we shall exam-

ine in a fair amount of detail the 35 basic

PIC commands. It is hoped that this will

give you all the necessary information that

will enable you to conceive a design in

which you can use a PIC16F84 to control

whatever situation you wish, and to write

the code that will let it do so.

There is, though, much more to writing

programs than you may at this moment

fully appreciate. Knowledge about individ-

ual commands and the way in which they

can be used is not enough in itself.

Programming is a way of looking at the

world that other people may not recognise.

You must have the mental ability to see

each programming situation as a step by

step function, visualising and analysing in

your mind exactly how it is that you need

to specify the complete program flow.

You have to write the sequence of events

with the correct grammar, with the correct

spelling and in the correct order.

Undoubtedly you will make mistakes

while you are writing the code, failing to

see the correct sequence of events and

using incorrect command structures.

You require the ability to analyse what

you have done wrong and to correct it. You

are likely to be confronted with an overall

task that may, on occasion, take you into

several days or even weeks of dedicated

concentration.

Readers have occasionally asked how

they can be taught to think like a program-

mer. There is no easy way in which this can

be taught. Some people have the ability,

some do not. The best way to learn is by

actually writing snippets of code and get

those to work, giving you the experience

and confidence to progress to more com-

plex situations. Throughout this

Tutorial

we try to encourage you in this approach.

Programming, to those who have the abil-

ity to see things “as they are” and not “how

they seem to be”, can become extremely

addictive. You could find yourself com-

pelled to get back to the keyboard and PIC

programmer at any conceivable hour. You

had better have an understanding family!

board mentioned earlier plus the few extra

components just listed.

TK3

already has

eight light emitting diodes (l.e.d.s), four

pushbutton switches and four uncommitted

(open-collector)

npn

transistors.

These facilities help to illustrate the pro-

gram examples discussed in the text and

encourage you to build up your experience

of how the PIC16F84 can be made to

respond to different practical situations.

In this text, we start at the very begin-

ning of programming. The first lesson is

about the very minimum of information

that needs to be written into a program list-

ing before the PIC can do anything else.

We then, “step by step”, take a specific

very simple task, such as turning on an

l.e.d., and describe in detail each of the

commands that are required to do the task.

Having described one task, we then take

that idea a stage further, adding a few more

commands that will enhance the capabilities

of the program. Each of these commands is

similarly discussed in detail. Thus we

progress, taking simple ideas, and illustrating

how they can be achieved and then enhanced.

We feel that this approach is far more

useful than describing each and every one

of the commands in turn before we ever get

to use them. Most people learn by doing,

reading about things in short sections and

applying the knowledge in practical bite-

sized chunks. A complete chapter on all the

commands in sequence would be too much

to remember and understand in one go.

The complete list of Microchip’s com-

mands for the PIC16F8x, PIC16F87x and

PIC16F62x families is shown in Table 1. All

are discussed and demonstrated. In the early

years of PICs there used to be two others,

OPTION and TRIS, but Microchip have

dropped them from their recent PIC families.

As you will see, there are a lot of “bit-

orientated” sub-commands available as

well as the main commands. Some of these

are similar in operation and close examina-

tion will be given only to the principal ones

– once you understand these, use of the

similar bit-setting commands available will

become obvious.

types of microprocessor or microcon-

troller, will find that once a few commands

have had their functions explained, using

them will rapidly become instinctive. The

author, having many years of such experi-

ence, effectively learned about PICs and

how to use them over a single weekend,

just by doing a bit of experimenting.

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