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PICKING

THE Perfect

Picking the perfect microcontroller

FEATURE

Top

The Arduino Uno

is still widely used,

but lacks some of

the more advanced

features of more

powerful options

Above

The Mbed LPC1768

provides an ARM

Coretex M3 in

breadboard-friendly

packaging

moment to

consider it as a

processor choice as

much as a board choice, and

have a look at its ecosystem and

the record of its manufacturer in

supporting it. It’s unpleasant to spend time and effort

learning to use a platform only for it to suddenly

disappear. Intel for example put a lot of resources into

promoting its x86 microcontrollers at this level, only to

pull the Galileo, Joule, and Edison products from the

market and leave developers

working on these platforms

without any hardware to use.

So among the multiple CPU

families to be found, we’ll look

at a few of the common ones in

the hacking and making

community. We’ll start with

Microchip’s PIC series of

processors, as they are

probably one of the oldest

families still in the game. Their origins lie in an early

1970s I/O peripheral for a 16-bit microcomputer, but

they became popular at the hardware hacker level over

20 years ago, as single-chip versions with on-board

flash appeared that could be easily rewritten with user

code. The PIC is an astonishingly versatile family, with

everything from tiny 6-pin SOT23 to very powerful

32-bit variants, and you will find them in many of your

electronic devices. They suffer from the disadvantage

though that writing PIC software is not easy to get

started in, and that their IDE and toolchain for

developers is proprietary and quirky. While it does have

some great uses for professional engineers, this

difficulty in getting started means that it’s not widely

used by hobbyists.

FULLY ARMED

The ARM series of processors have their origins in the

1980s, as the innovative RISC device that powered the

Acorn Archimedes series of computers. Since then

they have evolved to a series of related processor

cores designed for everything from low-power

microcontrollers to high-power general-purpose

computers, and through a system of licensing can be

found in products from multiple different

semiconductor manufacturers. The multicore

powerhouses that lie behind your tablet, smartphone,

or even boards like the Beagle or the Pi, are not the

ARMs that interest us here – instead it will be its

Cortex M series of microcontroller cores that you will

find in products at this level.

The final processor family we’ll mention here is

Espressif’s ESP8266. This differs from the others in

that it comes from a Chinese company and is a

microcontroller designed for the specific application of

wirelessly connected IoT devices. It contains a 32-bit

ATMEL

AVR

We haven’t looked

at the main Arduino

products, or Atmel’s

AVR chips, here

because we’re

exploring the lesser-

known options (for

a detailed look at

the former, read our

Arduino feature from

issue 1, available

online at hsmag.cc/

mYfVuw). While the

ubiquitous Arduino

Uno makes a great

first board, it’s useful

to look beyond this

comfort zone to

see what other

options are

available. Even

if you decide that

the Arduino boards

are right for you, by

checking out the

other options, you’ll

learn more about

the board you are

using. You’ll also find

out what the other

possibilities are, and

your next project

might just need an

extra feature that you

can’t get with your

first choice.

THE ARM SERIES OF PROCESSORS HAVE

THEIR ORIGINS IN THE 1980S, AS THE

INNOVATIVE RISC DEVICE THAT POWERED THE

ACORN ARCHIMEDES SERIES OF COMPUTERS