CMPE 246 Computer Engineering Design Studio

WORK IN PROGRESS

Embedded System

• Multiple components (hardware AND software) combined to perform a set of dedicated functions

• Generally includes:

  • Microprocessor

  • RAM and ROM

  • ADC

  • Firmware

Big Bang Model

• Type of design flow model

• No planning or process before developing a system

Spiral Model

• Type of design flow model

Loops through a development cycle of 4 phases:

• Planning

• Risk analysis

• Engineering

• Evaluation

Waterfall Model

• Type of design flow model

• Linear process where the next step cannot start until its previous step is finished.

Code-and-Fix Model

• Type of design flow model

• Requirements are defined but there is NO plan of the process before development

The V-Model

• Type of design flow model

• Similar to the waterfall model but with each step paired with a step for testing.

ARM processor

Processor of a smaller size in which power efficiency is prioritized

ROM

• “Read only memory”

• Stores code (AKA instructions) permanently

RAM

• “Random Access Memory”

• Stores temporary information

PROM

• “Programmable ROM”

• Purchased empty, programmed only once

EPROM

• “Erasable and reprogrammable ROM”

Microprocessor

Takes in a task and processes it into instructions for (hardware or software??)

Advantages of Embedded System

• Cheap

• Portable

• Small

• Low power consumption

• High performance and accuracy

API

• “Application Programming Interface"“

• Takes instructions from user (picks from API documentation), transfers info to the application of API (info is translated for the software of interest

Drivers

• Piece of a software that allows communication between the and hardware

SRAM

• “Static Ram”

• Retains content as long as electric power is applied to chip

DRAM

• “Dynamic Ram”

• Retains content for an extremely short amount of time

  • About 4ms

Masked ROM

• Stores data permanently

• Contents of memory is specified before chip is produced

EEPROM

• “Electrically Erasable Programmable ROM”

• Type of hybrid memory

• Can be erased with electric power and reprogrammed

• For small, frequently read/written data

Flash Memory

• Type of hybrid memory

• Retains data without power

• For larger, bulk data storage

NVRAM

• “Non-Volatile RAM”

• Type of hybrid memory

• Fast, persistent data storage for speed

OS Kernel Mode

• Has unlimited access to hardware while OS is running

  • Basically core component in OS that has control over whole system

• Doing management of which tasks are running

  • Makes CPU process the higher priority tasks

  • Manages allocation of devices connected to the system

    • Mouse, keyboard, e.g.

  • Allocates and deallocates memory space of processes to ensure all has enough space to complete their execution

  • Shares resources amongst the processes

    • Acts as bridge between users and system resources

• Resides in middle of software and hardware to ensure their interactions

OS User Mode

• Limited access to CPU and memory

Process/Task

• Executed program/part of a program

• Program runs, gets processed and split up by the OS, and turns into a task

Live Code

• Code that is actively being run

• AKA code currently going through the OS

Prefixes For Storage

Done in 2^n instead of 10^n

Ex:

• Gigabyes = 2^30 bytes

• Kilo = 2^10 bytes

PROM

• “Programmable ROM”

• ROM manufactured as blank ROM so user can edit it later.

EPROM

• ROM where it’s data can be erased and reprogrammed

• Requires strong UV light to erase the data

  • Dont ever use ts bruh

Buses

• System that only transmits information

• Ex.

  • Cables

  • Wifi

  • Bluetooth

  • Lasers

Buffer

• Type of memory where one device’s processor will send information into another’s “buffer”

System Bus

• AKA memory bus

• Connects the CPU and main memory of computer

Actuator

Takes electric signal and blends with energy source to create movement

Cyber-Physical System

• CPS

• Integration of embedded systems to translate digital information into the physical world

IDE

• “Integrated development environment”

• Type sh

Embedded Testing

• Literally just Software and hardware verification and validation

  • AKA V&V

  • Verification: “yeah this does what we designed it to do”

  • Validation: “yeah the people and environment say it’s doing what they want it to do”

Firmware

• Code embedded into hardware

• Ex. Every time washing machine turns on, the firmware ensures it functions the same each time

Bare Metal

• Where developers to directly program hardware without OS

• Complete control over hardware pieces

ISP

• “In-system programming”

• Chips of which are already programmed before soldering onto a board

Upgrading Firmware

Two ways:

Flashing

Process of changing the firmware

• Erases and replaces the ROM inside microcontroller

Compiler

• Converts from high level code into assembly code (AKA binary)
  

• (Optional?) Two types:

  • Each line is compiled and sent to the processor one at a time for real time changes

  • Compiles everything and sends to processor, but if changes are made everything will have to compile again (basically translates to .exe files)

  • (shorten the examples?)

Executable File

• .exe file

• File that is of compiled code????

Assembly Code

• Code of which is in binary form

• Used so the processor can understand and complete the tasks

Communication Network

Does three things:

1. Data exchange: allows devices, sensors, and actuators to transfer/exchange data

2. System integration: connects multiple devices

3. Remote and control monitoring: remote supervision. firmware updates, and control commands

Physical Ports

• Physical connection points

• Ex.

  • Ethernet ports

  • Usb ports

Logical Ports

• Logical connection point

• Routes data

• Ex.

  • TCP/IP

  • HTTPS

    • Brewing secure websites

  • FTP

    • File transfers

Protocols

• Set rules and conventions on how data is formatted, transmitted, processed, and errors detected and corrected

Wireless Communication Protocol

• Enables data transmission over air without physical connectors

• Key characteristics:

  • Mobility: data moves without cables

  • Flexibility: scalable and adaptable to varies environments

  • Range: range varies: low data rate w/ long range and the opposite

  • Interference and security: Can be interfered with

BAN

• “Body area network”

• Literally just network of devices operating in or on a body

WAN

• “Wide area network”

• Network of devices +-10 meters away from your body

PAN

• “Personal area network”

LPWAN

• “Low power wide area network”

• idfk

Embedded System Architecture

• Embedded system contains of multiple components working together to perform tasks

3 Layers:

• Application software layer (optional)

  • High level software for system’s functionality + user interface

• System software layer (optional)

  • Manages operation of the hardware

• Hardware layer (required)

  • The foundation of the system

  • Hardware resides on a PCB

Printed Circuit Board

• PCB

• All hardware in embedded devices resides on the PCB

The Major Categories for PCB Hardware Components

1. Central processing unit
   CPU → the master processor

2. Memory
   Where system’s software is stored

3. Input Devices

4. Output Devices

5. Bus(es)
   The data pathway → “highway” across different components for data to travel across

Image example attached.

Embedded Processor

• Microprocessor for processing instructions and data

• AKA brain to interpret and carry out instructions from a program

Multi-core General Purpose Processors

• GPP (AKA the CPU) with multiple processors on a single chip

• Can have high power consumption

Clock Speed

• AKA processor or CPU speed

• Basically how many cycles the processor can perform in a second

  • Each cycle can perform 1 task per processor

  • In Hertz (Hz, and usually in GHz)

Cache

• Small amount of high-speed memory that stores frequently accessed data

  • To improve processor performance

Microcontrollers

• AKA SoC (System on Chip)

• Small, low-power processor to manage, control, and automate embedded systems

• Contains:

  • Program memory

    • Stores instructions

  • Data memory

    • Stores variables and other data

  • I/O pins

    • Input/output pins

    • Can connect external devices through these

Analog to Digital Converter

• AKA an ADC

• Converts analog signals to digital

  • Basically sin to square wave (1 and 0)

Digital Signal Processor

• AKA a DSP

• Microprocessors designed to process digital signals

Used in (e.g.)

• Audio and video processing

  • Audio equalization

  • Video rendering

• Microphone input processing

  • Noise cancelation

Single Board Computer

• AKA a SBC

• Uses a microprocessor instead of microcontroller

  • With IOs

  • And ram

Von Neumann Machine

• Type of processor architecture

Harvard Machine

• Type of processor architecture

Advantages of Embedded Systems

• Size of an embedded system can be very small

• Has lower power consumption

• Has high performance and accuracy

• Extremely cheap

• Very potable

• Keep glazing lil bro

Application Software Layer

• Top layer in the embedded system architecture

• Defines function and purpose of embedded devices

  • Can interact with users

System Software Layer

• Middle layer in the embedded system architecture

• Sub-layers:

  • Middleware

  • Operating system

  • Device drivers

Device Drivers

• Bottom layer in system software layers

• Software libraries that initialize the hardware

• Manage access to the hardware through application software later

• Helps communicate OS and other software with the hardware

  • Tells hardware to initiate its functions

Application Programming Interfaces

• AKA the APIs

• Set of rules and protocols that enables software programs to communicate and exchange data with one another

  • Basically acting like a middleman

• Client sends request to a website’s API, API processes request, sends back the appropriate response

Middleware

• Top layer in the system software layers

• 3rd party tool that supports (can use) APIs

• Basically anything that’s NOT OS kernel, device drivers, or application software

Operating System

• Middle layer in system software layers

• AKA the OS

• Set of software libraries

  • Provides abstraction layer to make development of middleware and software application layer easier

  • Copies a program and cuts it down sequentially into tasks that are sent to the processors.

• Is split up into user and kernel mode

Kernel Space

• Separate memory space where kernel executes processes and services

User Space

• Memory space on system for user applications

• Basically everything except Kernel operates here

Multitasking

• Ability to execute more than one task/process at a time

• NOT executing at the same time, but allowing more than one task to advance over a over a period of time

  • E.g. 3 tasks: task 1 executes 50%, then task 2 executes 50%, then task 3 100%, then task 2 50%, and finally task 1 at 50%

Thread

Executed program that is using the same space as the other programs

Real-Time Operating System

• AKA the RTOS

• OS that can manage and support the completion of multiple tasks/processes with different deadlines without missing any

The Layers of Programming Languages

Machine Language

• Type of programing language

• Represented in binary or hexadecimal form

• Only language hardware can directly execute

Assembly Language

• Type of programming language

• Intended to communicate directly with a computer’s hardware

Shell

• Program that links the user and the operating system together

• Examples

  • cmd.exe

  • File explorer

• Basically you can send tasks to the OS

I/O Components

• Moves information into and out of the board

  • To and from the master processor

  • In serial, parallel, or both

• Made up of

  • Transmission medium

    • Wired/wireless medium connecting I/O to embedded board for data communication and exchanges

  • Communication port

    • Connected to the transmission medium or receives a wireless signal

  • I/O controller

    • Slave processor (basically not the main one) that manages the I/O device

  • I/O buses

    • Connects I/O and master processor

I/O Controllers

• Bridges communication between the CPU, memory, and I/O devices

• Devices usually require an I/O controller

• Also acts as a buffer during data transfer

Serial Interfaces

• Manage serial data transmission and reception between master CPU and I/O device or controller

System Bus

• AKA memory bus

• Connects CPU and main memory of the computer

Expansion Buses

• AKA Input/Output (I/O)

• Connect peripheral devices to the CPU

  • Such as the mouse, keyboard, and a headset

Sensor

• Electronic instrument that translate real-world parameters into electrical signals

Actuators

• Device that creates movement using an electrical signal in combination with an energy source