Embedded Systems CP105

Programming with Embedded Real-time Operating Systems

Certificate Program

John Hatch

University of Washington

Copyright 2013

Course

General

• Course Outline
• Course Overview
• Course Books

Discussion Forum and Collect It

• Assignment Drop Box
• Discussion and Class Forum

Introduction

• Overview of Embedded Systems
  • Discussion
  • What are Embedded Systems?
  • What’s Not an embedded System?
  • What makes it an Embedded System?
  • Comparisons
  • Embedded Design Challenges
  • Life Cycle Differences
  • Killer of Embedded Projects
  • HW / SW Tradeoff
  • Software Architecture Creating SW Modules
  • Input, Process, Output example
  • Implementation
• Real-Time
• Real World Example
  • Real World Timing Requirements
  • Windows CE Test Results

Exception Handling

• Register Organization
• Modes and Exception types
• Privileged modes
• Current Program Status Register (CPSR)
  • Condition Bits
  • Interrupt Bits
  • Thumb Mode Bit
  • Mode Bits
• Status Register Instructions
  • MRS - Move to Register from Status
  • MSR - Move to Status from Register
• Interrupt Control
• Vector Table
• Exceptions
  • Exception Actions
  • Returning from Exception
  • Stack Handling
  • Program Counter (PC)
  • Reset Exeception
  • Undefined Exception
  • SWI - Software Interrupt Exception
  • Prefetch Abort - Instruction Fetch Memory Abort
  • Data Abort - Data Access Memory Abort
  • IRQ - Interrupt Request Exception
  • FIQ - Fast Interrupt Request Exception
  • Exception Priorities
• How to Cause Different Types of Exceptions
• Prefetch Abort Behavior
• Nesting Interrupts
• ARM Calling Standard
  • Argument registers
  • Register Variables
  • Link Register
  • Stack Pointer
  • Static Base
  • Frame Pointer
  • Argument Passing
  • Return Result
  • Comments
  • Possible optimizations
• uDebugger Assignment
  • Overview
  • Objective
  • Concept
  • Steps
  • Challenge
• Debugger Discussion
  • uDebugger
  • Interrupts to multi tasking

Context Switching

• Developing the Context Switch handler
• Timer for exceptions
• Exception Handler Steps
  • Fix up LR
  • Scratch Registers
  • Save SPSR, LR, and SP
  • Reset the IRQ stack pointer
  • Switch to Supervisor mode
  • Start saving register to the task’s stack
  • Copy values from IRQ stack to the Supervisor stack
  • Save the task’s CPSR
  • Saving the stack pointer for later
  • Restore a task
• Starting a Task from Scratch
  • Initial configuration of the stack
• Context Switch Assignment
  • Instructions for implementing the context switch

Tiny OS

• Tasks
  • Task Stack
  • Task States
  • Task Control block
• Critical Sections
• Delay Timer
  • Scheduler
• Adding Semaphores Part One
  • Outline of changes to TinyOS
  • Using Lists
  • TaskBlock Change
  • EventBlock
  • Block Lists
  • Initializing Lists
  • Change to CreateTask
  • Change to the Scheduler
  • List Helper Functions
• Adding Semaphores Part Two
  • Creating a Semaphore
  • Pending on a Semaphore
  • Posting to a Semaphore
  • Deleting a Semaphore

Synchronizing and Sharing Data

• Data Sharing & Protection
• Data Sharing & Protection
• Scenarios
• Synchronization and Sharing techniques
• Synchronization Issues
  • Data Corruption
  • Dead Locks
  • Race Conditions
• Priority Inversion
  • Description
  • Consequences
  • How it happens
  • Mitigation
• Data Sharing & Protection
• Examples
  • Single Thread plus Interrupt
  • Multiple Threads (no interrupts)
• Data Sharing Protection Solutions
  • Disable Task switching
  • Disable Interrupts
• Semaphores
  • Semaphore pseudo code
  • Using a Semaphore
  • Deadlocks
  • Priority Inversion
• Deadlocks
  • What does a semaphore mean in a system?
  • Semaphore Deadlock examples
  • Threads at point A & B
  • Semaphore Deadlock example solution
• Priority Inversion
  • Priority Inversion example
• Re-entrant Code

Synchronization Patterns

• Delay Polling
• Delay Polling Task
• Wait and Run
• Signaling
  • Signal
  • Signaling from an ISR
• Protected Access or Serialize
  • Serialized Print
• Signal and Wait
• Shared Data
  • Using semaphores to share data.
• Multiple Access
  • Rule to prevent deadlocks
• Producer/Consumer

uCOS Introduction

• uCOS Startup
• uCOS Startup Walk Through
• uCOS Port - Review and Notes
  • Interrupt Control
  • Timer
  • Ticks
  • Defines
  • Startup
  • Application
• Startup Assembly File
  • startup.s
• uCOS Start Functions
  • OSInit
  • OSStart

uCOS Tasks

• Tasks
  • Task Stack
  • Task States
• uCOS Task Functions
  • OSTaskCreate
  • OSTaskCreateExt
  • OSTaskDel
  • OSTaskDelReq
  • OSTaskChangePrio
  • OSTaskSuspend
  • OSTaskResume
  • OSTaskStkChk
  • OSTaskNameSet
  • OSTaskNameGet
  • OSTaskQuery
• Task Control Block
• ucos_ii.h
  • Defines
  • Events
  • Message MailBox, Memory, and Semaphores
  • Tasks
  • Timer
  • Globals
  • Function Prototypes
  • Application Function Prototypes

uCOS Interrupts and Context Switches

• How does uCOS handle interrupts
• uCOS Timer
• How does a context switch work in uCOS

• uCOS Interrupts

uCOS Indepth

• OS
  • OSInit
  • OSStart
  • OSSchedLock
  • OSSchedUnlock
  • OSStatInit
  • OSVersion
  • OSEventNameGet
  • OSEventNameSet
• Critical Sections
  • Requirements for critical sections
  • Functions
• Time
  • OSTimeTick
  • OSTimeDly
  • OSTimeDlyHMSM
  • OSTimeDlyResume
  • OSTimeSet
  • OSTimeGet
• Semaphores
  • OSSemCreate
  • OSSemDel
  • OSSemPend
  • OSSemPendAbort
  • OSSemPost
  • OSSemAccept
  • OSSemSet
  • OSSemQuery
• Mutexes
  • Priority Inversion
  • OSMutexCreate
  • OSMutexDel
  • OSMutexPend
  • OSMutexPost
  • OSMutexAccept
  • OSMutexQuery
• MailBoxes
  • OSMboxCreate
  • OSMboxDel
  • OSMboxPend
  • OSMboxPendAbort
  • OSMboxAccept
  • OSMboxPost
  • OSMboxPostOpt
  • OSMboxQuery
• Queues
  • OSQCreate
  • OSQDel
  • OSQPend
  • OSQPendAbort
  • OSQAccept
  • OSQPost
  • OSQPostFront
  • OSQPostOpt
  • OSQFlush
  • OSQQuery
• Event Flags
  • OSFlagCreate
  • OSFlagDel
  • OSFlagPend
  • OSFlagAccept
  • OSFlagPost
  • OSFlagQuery
  • OSFlagPendGetFlagsRdy
  • OSFlagNameSet
  • OSFlagNameGet
• Timer

Memory Management

• Memory Management
  • Static Allocations
  • Stacks
  • Heaps
  • Memory Fragmentation
  • Handling Memory Fragmention
  • Partition Manager
  • uCOS Memory Partitioner
• Memory Partitioner
  • Memory Management
  • Memory Control Blocks
  • Using Memory Partions
• uCOS Memory Functions
  • OSMemCreate
  • OSMemGet
  • OSMemPut
  • OSMemQuery

Drivers

• Drivers
  • Rational
  • Problems C++
  • Driver Setup
  • Using the Drivers
• Creating a Driver
• MP3 Player Driver
  • Task Code
  • GetMP3
  • MP3 Driver Write Function
  • MP3 Helper Macros
  • SPI Write Function
  • SPI Helper Macro
• Driver Code
  • driver.h
  • driver.c
  • drv_mp3.h
  • drv_mp3.c
  • drv_spi.h
  • drv_spi.c

Music Player Project

• Music Player Project
  • Objective
  • Overall Requirements
  • Requirements
  • Optional Requirements
  • Project Hints
• MP3 Commands
  • Sending Commands to the MP3 player
• Design
  • Design Objectives
  • Design Patterns
  • Top Down Diagram
  • Possible Design
• Code
  • driver.c
  • drv_spi.c
  • drv_mp3.c
  • tasks.c

Operating Systems

• Operating Systems
  • Overview
  • What is an Operating System
  • Theme
  • Embedded OS vs. General Purpose OS
  • What Features are Needed?
  • Development Approaches
  • Monolithic
  • Monolithic Example
  • In-house -proprietary OS
  • Off the shelf OS
  • Minimum OS Features
  • Preemptive vs. Non-preemptive OS
• Operating System Internals
  • Process
  • Simple System
  • Process and Thread Control APIs
  • Scheduling
  • Scheduler
  • Scheduling algorithms
  • Task States
  • Round Robin Scheduling
  • Dynamic Priority Scheduling
  • Real-time scheduling algorithms
  • Rate Monotonic Scheduling
  • Earliest deadline first
  • Least Laxity
  • Simple Round-Robin
  • Simple Round-Robin with Interrupts
  • With Function Queue Scheduling
• Code to Running Process
  • Parts of the system
  • Compiler
  • Linker
  • Kernel
• Translation Lookaside Buffer
  • Two Level Page Table
  • Page Tables

• Windows_CE_Architecture.pdf
• Virtual Memory
• Shell and Flashing

Assignments

For the assignments details and due dates see the Assignment Drop Box.

• uDebugger Assignment
• Context Switch Assignment

Final

EMBSYS CP105 - Final.docx

Project Files

File	Description
uDebugger_Homework.zip	uDebugger homework project
Context_Switcher_Homework.zip	Context switcher homework project - LPC2378
TinyOS_Homework.zip	TinyOS homework project - critical sections and timer delays
TinyOS_Homework_VIC.zip	TinyOS homework project with VIC support
TinyOS_Events_LPC2478_Homework.zip	TinyOS homework project with Event Blocks and semaphores
uCOS_Port_Homework.zip	uCOS Port homework project - LPC2378
uCOS_2_LPC2478_Homework.zip	uCOS Port homework project - LPC2478
Semaphore_Homework.zip	Semaphore homework for TinyOS and uCOS
uCOS_2_Music_LPC2478_Homework.zip	uCOS Music drivers homework project - LPC2478
MP3_Player_LPC2378_Homework.zip	MP3 Player Homework project for LPC2378 (last year)

Sample Files

File	Description
AudioDevice_Demo_2478.zip	Full feature Audio Demo for LPC2478 - ported but doesn’t build.
LCD_Demo_2478.zip	LCD Demo project for the LPC2478 - builds and runs.
LPC23xx_Sample_Software.zip	LPC23xx sample software for device peripherals

Extra Files

File	Description
TinyOS_Shell_LPC2478.zip	TinyOS with Shell
TinyOS_with_Priorities.zip	First draft of TinyOS with Priorities - os files only
lpc2478.h	Register definitions header file for NXP LPC247x devices. Ported from IAR version.

Hardware

• LPC2378_STK
• LPC2478_STK
• Olimex JTAG
• MOD-MP3
• VS1002 Audio Decoder Chip
• MOD-MP3-X
• VS1053 Audio Decoder Chip
• Vectored Interrupt Controller
• Serial Peripheral Interface Bus
• 6610 Serial Color Graphic LCD

uCOS Port

• Micrium uCOS-II ARM Port
• Exception Handling Sequence for IRQ
• uCOS Port Dependent Functions
• uCOS Port - Code

Build

• Linker Definition File

Setup Guides

• Eclipse Installation Guide
• Flash Magic
• Serial Terminal Emulator

Tools

• Tools
• OpenOCD
• GCC

General Resources

• Projects