Chapter 1 Introduction
About content
Be cautious, just to cope with the exam, basically no nutrition.
About the exam
The twelfth week will be answered in the classroom at 2 pm on Monday, and the test will be conducted at 2 pm on Wednesday of the twelfth week. The exam classroom is being applied. The exam time is 90 minutes. System structure) to Chapter 5, the test questions: one fill-in-the-blank questions, two true and false questions, three short answer questions, four assembly questions, five programming questions.
2. Definition and architecture of embedded system
Definition of embedded system: (3 versions)
(1) A dedicated computer system with application as the center and computer technology as the basis, software and hardware can be tailored.
(2) Computer systems for embedded applications
(3) Special software and hardware systems with microprocessors.
Real-time systems (RTOS) need to complete tasks within a specified time and make deterministic predictions. The positive determination of real-time systems is mainly divided into:
(1) Logic correctness
(2) Time correctness
According to the real-time accuracy, it is mainly divided into:
(1) Hard real-time: higher time accuracy
(2) Soft real-time: less time accuracy requirements high
Features of the embedded system:
(1) Small system core
(2) Simplified system
(3) Strong specificity
(4) High real-time
(5) Standardization of software development
(6) Development tools and environment are required
The composition of the embedded system:
- Software subsystem
- operating system
- application
- Hardware subsystem
- processor
- Memory
- Input and output interface
- Peripherals
Level: functional level → \rightarrow→ Software layer→ \rightarrow→ Middle layer→ \rightarrow→ Hardware layer
The core of an embedded system is an embedded microprocessor.
Embedded processor classification:
(1) MCU: Single chip microcomputer, characterized by monolithic, volume, power consumption, low cost
(2) DSP: dedicated to signal processing
(3) MPU: evolved from general-purpose computer CPU, only reserved Embedded-related hardware
(4) SoC: Embedded system on chip, a circuit system that integrates functional blocks on a chip
The software foundation of the embedded system is RTOS, and its main functions are:
(1) CPU management
(2) Memory management: MMU
(3) Device management
(4) Programming interface
μCOS: Microcontroller operating system.
Advantages of embedded systems: (compared with single-chip computers and PCs)
(1) Performance: processing capability≫ \gg≫Single- chip microcomputer, close to PC, but smaller in size
(2) Real-time: RTOS strong real-time
(3) Human-computer interaction: support for graphical user interface
(4) System upgrade: fast upgrade
Embedded ≠ \ne= Single-chip computer (operation, software and hardware design, with or without operating system)
embedded≠ \ne= PC (dedicated/general purpose, resources, operating system, power consumption)
Embedded peripherals: memory, interface, display device, etc.
Middle layer → \rightarrow→The hardware abstraction layer is located between the software layer and the hardware layer.