Practical_Electronics-May_2019

The current version of MPLAB X

IDE is v5.15, other versions close to

this should be compatible with the

project source files we will provide

on-line. Installation is straightforward,

and typically you accept all the default

settings offered. Once the IDE installa-

tion completes and you have clicked

‘Finish’, your web browser should

open several webpages on the Micro-

chip website. Select the page titled

‘MPLAB- XC Compliers’ and select

the ‘MPLAB XC8 Complier’ download.

Installation is again straightforward,

accepting the default option present-

ed. Once completed, installation of the

compiler will be automatically incor-

porated into MPLAB IDE – there are

no additional set-up steps required.

Besides the software installation you

will also require a PICkit 3 or PICkit 4

debugger device to load code onto an

actual processor. Bear in mind that on a

device of this size, debugging software

(i.e., single-stepping through each line

of execution) is not possible without

an optional adaptor board. As our pro-

grams are going to be very small, and

very simple, we have decided not to

worry with this additional cost.

Do download the datasheet for the

PIC10F200 family, which can be found

here: http://bit.ly/pe-may19-mc2

Power of C

The assembly language instruction set

of the PIC10F is very similar to other

PIC processors you may be familiar

with, including the PIC16 and PIC18

products. For the most part, however,

this will not be relevant, as we will be

developing our software in the high-

er-level programming language ‘C’.

We will demonstrate how efficient

the ‘C’ compiler is, and what tricks we

can apply to improve that efficiency

when the compiler converts our code

into assembly language. While there

are only 512 words of Flash memory,

the efficiency of the PIC microcon-

troller architecture means each one of

those words can

hold a complete

single assem-

bly instruction.

Most instructions

occupy a single

word of memory.

‘C’ language pro-

gram statements

can occupy be-

tween one and six

instructions typi-

cally, depending

on the complexi-

ty of the particular

instruction.

Our first project

For our first project we will attempt

to create the ‘smart power switch’ de-

scribed above. The circuit for this is

shown in Fig.4. A relay will be incor-

porated to allow switching of higher

voltage circuits, but we recommend that

you do not attempt to do so on Vero-

board or breadboard. The IRL510 FET

is powerful enough to switch 1A loads

directly, so the relay may well be op-

tional. What this circuit could be used

for we’ll leave to your imagination! For

lower current loads the FET could be

replaced by a simple NPN transistor.

In summary

If you think this device is only for

novelty functions, think again. It can

provide valuable services as a sub-set

of a larger circuit (just as the venerable

NE555 timer chip has done for decades.)

The author has just completed a com-

mercial project where the PIC10F200

was the central microcontroller and

has been deployed in the thousands.

In that example, the code space used

by the application was just 80 words,

35% of the available space, all written

in ‘C’. This is a device that is definitely

worth taking seriously.

While these parts are readily available

from the usual electronics distributors,

such as Farnell and RS Components,

delivery charges may be significantly

higher than the actual device costs –

these chips cost as little as 50 pence.

eBay and Amazon can be a good source,

however, just take care to check on

the postage and packaging fees. Also,

be careful to order the correct part

• the plastic DIL package version is
  PIC10F202-I/P, while the six-pin sur-
  face mount part is PIC10F202T-I/OT.

Next month

In Part 2, next month we will look at

how the ‘C’ compiler within MPLAB can

be configured to reduce the code space

used, build the first circuit and explore

the code required to bring it to life.

• USB


• Et hernet


• Web server


• Modbus


• CNC (Mach3/ 4)


• IO


• up t o 256
  microst eps


• 50 V / 6 A


• USB confi guration


• Isolat ed


• up t o 50MS/ s


• resolut ion up t o 12bit


• Lowest power consumpt ion


• Smallest and lightest


• 7 in 1: Oscilloscope, FFT, X/ Y,
  Recorder, Logic Analyzer, Protocol
  decoder, Signal generator


• up t o 32
  microst eps


• 30 V / 2. 5 A


• PWM


• Encoders


• LCD


• Analog inputs


• Compact PLC

http://www. poscope. com/ epe

PoScope Mega1+

PoScope Mega50

1

2

3

4

8

7

6

5

NC

VDD

GP2

GP1

GP3

VSS

NC

GP0

IC1

PIC10F202

External

control

circuit

Relay

C1

100nF

R1

330Ω

R2

1kΩ

R2

10kΩ

TR1

IRL510

V+

V–

D1

Green

D1

1N4148

S1

Fig.4. Our first PIC10F202 project schematic