Introduction to uCOS II v2 6 m11

Introduction to uCOS-II V2.6


About SwiftACT
• A Technology services startup company
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Under establishment

• Areas of specialties:
o
o

Mobile telecommunication services development
Embedded systems development

• Types of services:
o
o
o
o

Consultation
Managed services
Sourcing
Training

Amr Ali Abdel-Naby@2010

Introduction to uCOS-II V2.6

About Me
• Graduated 2004
o

ECE, ASU: 5 yrs distinction

• 5+ years in embedded systems development
o

SDLC, Apps, MW, DD, Porting, ...

• 3+ years in SW engineering
o

PSP, CMMI, Systematic reuse, ...

• 3+ years in SW testing
o

IBM certified, ISTQB certified, ...

Amr Ali Abdel-Naby@2010

Introduction to uCOS-II V2.6


Copyright
• Materials in this course is the property of Amr Ali Abdel-Naby.
• Reproduction or transmission of the materials in any manner

without the copyright owner permission is a law violation.

Amr Ali Abdel-Naby@2010

Introduction to uCOS-II V2.6


Course References
• MicroC/OS-II The Real-Time Kernel, 2nd Edition, by Jean J.
Labrosse

Amr Ali Abdel-Naby@2010

Introduction to uCOS-II V2.6


Obtaining the Status of a Semaphore,
OSSemQuery
INT8U OSSemQuery (OS_EVENT *pevent, OS_SEM_DATA *pdata)
•
•
•

pevent: A pointer to the desired semaphore
pdata: A pointer to the returned semaphore information
Return value:
o
o
o

•

No error
pevent is not a semaphore.
pevent is null.

Now lets see OSSemQuery in os_sem.c

Amr Ali Abdel-Naby@2010

Introduction to uCOS-II V2.6


Porting µC/OS-II

Amr Ali Abdel-Naby@2010

Introduction to uCOS-II V2.6


Outline
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Introduction
Development Tools
Directories & Files
INCLUDES.H
OS_CPU.H
OS_CPU_C.C
OS_CPU_A.ASM
Testing a Port
Lab 8: 80x86 Port – Real Mode, Large Model with Emulated
Floating Point
• Summary

Amr Ali Abdel-Naby@2010

Introduction to uCOS-II V2.6


Outline
•
•
•
•
•
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Introduction

Development Tools
Directories & Files
INCLUDES.H
OS_CPU.H
OS_CPU_C.C
OS_CPU_A.ASM
Testing a Port
Lab 8: 80x86 Port – Real Mode, Large Model with Emulated
Floating Point
• Summary

Amr Ali Abdel-Naby@2010

Introduction to uCOS-II V2.6


What is Porting?

“The process of adapting SW so that an executable program can be
created for a computing environment that is different from the one for
which it was originally designed for”

Amr Ali Abdel-Naby@2010

Introduction to uCOS-II V2.6


Porting in PC World
• x86 is the dominant CPU architecture.
o

A lot of SW are never ported to different CPUs.

• Windows & a Unix flavor are the dominant operating systems.
• International standards facilitate porting in the PC world.
o

ISO, POSIX, …

• Porting is rare in our world.

Amr Ali Abdel-Naby@2010

Introduction to uCOS-II V2.6


Porting for Embedded Systems World
• Embedded systems are custom by nature.
o
o
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CPUs
Operating systems
...

• Portability is a significant problem.

Amr Ali Abdel-Naby@2010

Introduction to uCOS-II V2.6


Layered Architecture & Porting
Application SW
Application Porting

Middleware
Middleware Porting

Operating System
OS Porting

Firmware / Device Drivers

HW

Amr Ali Abdel-Naby@2010

Introduction to uCOS-II V2.6


OS Porting
• The most difficult type.
• OS provides HW abstraction.
• Needs solid HW Knowledge as well as solid HW knowledge

Amr Ali Abdel-Naby@2010

Introduction to uCOS-II V2.6

Types of OS Porting
OS Porting

Architecture

Basic
Board
BSP

Amr Ali Abdel-Naby@2010

Introduction to uCOS-II V2.6


Architecture Porting
• The main task of OS is to support multitasking.
• Thus, architecture porting is about context switch & exceptions
handling.

Amr Ali Abdel-Naby@2010

Introduction to uCOS-II V2.6


Context Switch
• Volatile state of the CPU
o

CPU registers + MMU if OS is process based

Task A Stack(memory)

Task A TCB

cpsr
r0
r1
r2
r3
r4
r5
r6
r7
r8
r9
r10
r11
r12
r14 (lr)
r15 (pc)

Stack ptr

Task B TCB
CPU Core

Stack ptr

CPU Register

Save

Scheduling Decision Made

Restore

Current running

Context
Switch

Task B
Task A
Context Switch Overhead

Amr Ali Abdel-Naby@2010

Introduction to uCOS-II V2.6

Task B Stack(memory)
cpsr
r0
r1
r2
r3
r4
r5
r6

r7
r8
r9
r10
r11
r12
r14 (lr)
r15 (pc)


Exceptions Handling

Amr Ali Abdel-Naby@2010

Introduction to uCOS-II V2.6


Board Porting
• Basic board porting
o
o

Check proper board operation
Function the minimum needed peripherals






Memory
ICU
PLL
Timer
I/O

• Board Support Package
o
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Boot loader + Device drivers
Minimum BSP is the basic board porting.

Amr Ali Abdel-Naby@2010

Introduction to uCOS-II V2.6


µC/OS-II Porting Prerequisites
• CPU support interrupts.
• CPU can generate interrupts at regular rates.
• Interrupts can be enabled and disabled.
• CPU supports HW stack.
• CPU can load & store stack pointer & CPU registers.

Amr Ali Abdel-Naby@2010

Introduction to uCOS-II V2.6

µC/OS-II Kernel Architecture
Application SW
(Your Code)
µC/OS-II
(Processor Independent
code)

µC/OS-II Configuration
(Application Specific)

µC/OS-II Port
(Processor Specific Code)
HW

Amr Ali Abdel-Naby@2010

Introduction to uCOS-II V2.6


Outline
•
•
•
•
•
•
•
•
•

Introduction
Development Tools
Directories & Files
INCLUDES.H
OS_CPU.H
OS_CPU_C.C
OS_CPU_A.ASM
Testing a Port
Lab 8: 80x86 Port – Real Mode, Large Model with Emulated
Floating Point
• Summary

Amr Ali Abdel-Naby@2010

Introduction to uCOS-II V2.6


Development Tools Requirement
• ANSI C compiler
o

Reentrant compiler

• Assembler
o

== C compiler with

 Inline assembly
 Registers manipulation from C

o

Saving & restoring registers

• Linker
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To combine object codes

• Locator
o

To place code & data anywhere in the memory map of the target
CPU

Amr Ali Abdel-Naby@2010

Introduction to uCOS-II V2.6


Outline
•
•
•
•
•
•
•
•

•

Introduction
Development Tools
Directories & Files
INCLUDES.H
OS_CPU.H
OS_CPU_C.C
OS_CPU_A.ASM
Testing a Port
Lab 8: 80x86 Port – Real Mode, Large Model with Emulated
Floating Point
• Summary

Amr Ali Abdel-Naby@2010

Introduction to uCOS-II V2.6


Directory Guideline
uCOS-II\CPU\Tool Chain
\OS_CPU.H
\OS_CPU_A.ASM
\OS_CPU_C.C

• For example:
uCOS-II\ARM\ADS1.2
\OS_CPU.H
\OS_CPU_A.ASM
\OS_CPU_C.C

Amr Ali Abdel-Naby@2010

Introduction to uCOS-II V2.6