Topic1ProgrammableDigitalElectronicSystems DigitalElectronicSyste, Apuntes de Ingeniería de Telecomunicaciones

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Department of Electronics

Academic Year 2015 - 2016

(ver 09- 07 - 2015)

Topic 1

Programmable Digital Electronic Systems

Digital Electronic Systems

Index

 1.1. Introduction  1.2. Embedded systems  1.3. Design of Digital Systems  1.4. The Microprocessor  1.5. Evolution of Microprocessors  1.6. Developing tools  1.7. Microprocessor based digital systems  1.8. Internal architecture of a microprocessor 2

Digital Electronic Systems

1.1. Introduction: What is a system?

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Digital Electronic Systems

1.1. Introduction

A system is characterized because it …

Interacts with the environment

Is divided into three stages:

 Input  Processing  Output 5

Digital Electronic Systems

1.1. Introduction: processing system classification

7 Supercomputers Servers Workstations Personal computers Calculators Specific computers Personal Computers+ I/O boards PLCs Digital regulators Microprocessor-based boards

• I/O boards + VME bus PC's + I/O boards + ISA bus Microcontrollers Scientific calculation Management (accounting, etc.) Databases Industrial Control Fly simulators Robotics Appliances Aeronautics Mobile robotics Mobile phones DO CONTROL / REAL TIME EMBEDDED NO EMBEDDED DO NOT CONTROL

Digital Electronic Systems

1.2. Embedded systems

Based on programmable devices

(e.g. microcontrollers, DSPs….)

In general, they are real-time reactive systems:

 They react to external events  They keep continuous interaction  They are continuously running  Their work depends on external time constraints

They perform several tasks concurrently

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Digital Electronic Systems

1.2. Embedded systems: board computer

Km/h Km Cont. Velocidad Tª Hora Embbeded computer Heating Air conditioning Injection system Pedals Wheels

1.2. Embedded systems: Examples

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Digital Electronic Systems

1.2.1. Embbeded system features

Concurrency

 All the tasks are carried out simultaneously by the system under control  The control system has to generate simultaneously the control actions  If there is only one processing unit: multiprocessing techniques are required, by using real time operating systems.  If there are several processing units, we are speaking about a multiprocessor solution. 11

Digital Electronic Systems

1.2.1. Embbeded system features

 Low power

 Many of these systems are powered by batteries.  Less consumption => greater autonomy  In many cases low voltage (3V) is needed

 Low weight

 Desirable feature in portable systems  It not only depends on the onboard computer and its peripherals but also on the supply system (batteries) or sensors and actuators 13

Digital Electronic Systems

1.2.1. Embbeded system features

 Low prices

 Related to consumer electronics and other devices with very competitive markets (e.g. mobile phones)

 Small size

 The size of an embedded system depends not only on itself but also on the space available on the system that controls and / or monitors. 14

Digital Electronic Systems

1.3. Design of Digital Systems

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 Standard circuits

 ASSP circuits (Application Specific Standard Part). ASIC chip, originally designed for a client and then offered to the general public  Microcontrollers and Microprocessors  Generic processors with embedded devices for specific applications.  DSP's  Device for Digital Signal Processing.  It has been designed for carrying out a small set of operations with a large amount of data.

Digital Electronic Systems

 From the wired machine to the programmed one

 WIRED:

 Mainly simple logic gates.  It is deterministic according to its inputs, very rigid with constant output  As the technology was introducing more complex logic functions  Its implementation was more difficult.  A huge amount of integrated circuits was needed for some arithmetic operations (multiplication, division, n order roots). ✌ In the early 70’s the PROGRAMMED MACHINE became only one electronic circuit: the MICROPROCESSOR

1.4. The Microprocessor

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Digital Electronic Systems

 Advantages of the microprocessor (uP)

 By changing the program a new function is obtained. In wired systems it is required to change the design, and some electronic circuits  Much easier to debug and to optimize applications.  Easy to update versions.  Easy to adapt the design to a different application.  Easy to design digital electronic circuits.  It is possible to work with analog signals by using A/D and D/A converters

1.4. The Microprocessor

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Digital Electronic Systems

1.5. Evolution of Microprocessors

 Evolution based on ideas, and not only on the technology

 At the beginning the evolution depended only on the technology  Goal: to increase the clock frequency  Efficiency is affected for more parameters:  Memory accesses (bottleneck)  Input/Output operations  Compilation  Operating System Overload  CPU 20