Page 12 - ARM Based Microcontroller Projects Using MBED

Preface

Traditionally,acomputerwasbuiltusinga high-level language such as C, C#, BASIC,
microprocessor chip and many external sup- PASCAL, JAVA, etc.
port chips. A microprocessor includes the The ARM processors are a family of CPUs
central processing unit (CPU), arithmetic basedon the reducedinstruction set computer
and logic unit (ALU), and the timing and con- (RISC) architecture, developed by advanced
trol circuitry, and as such it is not useful on its RISC machines (ARM). These processors are
own.Amicroprocessormustbesupportedby 32-bit and 64-bit optimized multicore chips,
many external chips such as memory, input- designed for higher speed and lower power
output, timers, interrupt circuits, etc. before it consumption than the traditional complex
becomes a useful computer. The disadvan- instruction set computers (CISC). Currently,
tage of this type of design was that the chip ARM processors are used in electronic
count was large, resulting in complex design devices, such as smartphones, tablets, games
and wiring and high-power consumption. consoles, multimedia players, and in many
A microcontroller on the other hand is ba- other consumer devices. The ARM processors
sically a single chip computer including a offer advantages of small size, fast through-
CPU,memory,input-outputcircuitry,timers, put, low cost, and low power consumption.
interrupt circuitry, clock circuitry, and sev- Consequently, most of the smartphones now-
eral other circuits and modules, all housed adays use a type of ARM processor.
in a single silicon chip. Early microcontrollers Many electronic companies offer ARM-
were very limited in their capacities and based processors with different overall archi-
speed and they consumed considerably more tectures and speeds. This book is about using
power. Most of the early microcontrollers the Nucleo family of microcontrollers in pro-
were 8-bit processors with clock speeds in jects. These are 32-bit ARM-based processors
the range of several MHz, and having only offering very high throughputs, large data
hundreds of bytes of program and data and program memories, large number of in-
memories. These microcontrollers were tra- put and output pins, peripheral support
ditionally programmed using the assembly modules such as universal asynchronous
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languages of the target processors. The 8-bit receiver/transmitter (UART), I C bus, serial
microcontrollers are still in common use, peripheral interface (SPI) bus, pulse width
especially in small projects where large modulation (PWM) support, timers, external
amounts of memory or high speed are not and internal vectored interrupt support,
the main requirements. With the advance- analog-to-digital converters, digital-to-
ment of the chip technology we now have analog converters, and many other features.
32-bit and 64-bit microcontrollers with The book has been organized as a project
speeds in the range of several GHz, and hav- book where the main theme has been to teach
ing over several GB of memories. Microcon- the use of the Nucleo microcontrollers by
trollers are nowadays programmed using a doing projects.

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