Introduction to uCOS II v2 6 m5
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Introduction to uCOS-II V2.6
About SwiftACT
• A Technology services startup company
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Under establishment
• Areas of specialties:
o
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Mobile telecommunication services development
Embedded systems development
• Types of services:
o
o
o
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Consultation
Managed services
Sourcing
Training
Amr Ali Abdel-Naby@2010
Introduction to uCOS-II V2.6
About Me
• Graduated 2004
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ECE, ASU: 5 yrs distinction
• 5+ years in embedded systems development
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SDLC, Apps, MW, DD, Porting, ...
• 3+ years in SW engineering
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PSP, CMMI, Systematic reuse, ...
• 3+ years in SW testing
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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
Outline
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Introduction to µC/OS-II
Kernel Structure
Task Management
Time Management
Semaphore Management
Mutual Exclusion Semaphores
Event Flag Management
Message Mailbox Management
Message Queue Management
Memory Management
Amr Ali Abdel-Naby@2010
Introduction to uCOS-II V2.6
Outline
•
•
•
•
•
•
•
•
•
•
Introduction to µC/OS-II
Kernel Structure
Task Management
Time Management
Semaphore Management
Mutual Exclusion Semaphores
Event Flag Management
Message Mailbox Management
Message Queue Management
Memory Management
Amr Ali Abdel-Naby@2010
Introduction to uCOS-II V2.6
Semaphores
• Semaphores are 16 bit unsigned integers used for resource
sharing or to signal the occurrence of an event.
OSSemCreate()
OSSemDel()
OSSemPost()
OSSemAccept()
OSSemPend()
OSSemQuery()
ISR
Task
N
Task
OSSemPost()
Amr Ali Abdel-Naby@2010
N
OSSemAccept()
Introduction to uCOS-II V2.6
ISR
Creating a Semaphore,
OSSemCreate
OS_EVENT *OSSemCreate (INT16U cnt)
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cnt: The initial value for the semaphore
o
o
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0 No resource available
N Resource initially available
Return value:
o
o
Non-null for successful creation
Null for failure
Amr Ali Abdel-Naby@2010
Introduction to uCOS-II V2.6
Deleting a Semaphore, OSSemDel
OS_EVENT *OSSemDel (OS_EVENT *pevent, INT8U opt, INT8U
*err)
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pevent: A pointer to the semaphore to be deleted
opt: Delete options
o
o
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Delete always
Delete if no pending tasks
err:
o
o
o
o
o
o
No error
Called from ISR
Invalid option
There are tasks pending.
pevent is null.
pevent is not a semaphore.
Amr Ali Abdel-Naby@2010
Introduction to uCOS-II V2.6
Deleting a Semaphore, OSSemDel
cont’d
OS_EVENT *OSSemDel (OS_EVENT *pevent, INT8U opt, INT8U
*err)
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Return value: Null if successful
Amr Ali Abdel-Naby@2010
Introduction to uCOS-II V2.6
Waiting on a Semaphore (Blocking),
OSSemPend
void OSSemPend (OS_EVENT *pevent, INT16U timeout, INT8U
*err)
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pevent: A pointer to the semaphore to pend to
timeout:
o
o
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0 wait for ever
!0 wait with specific timeout
err:
o
o
o
o
o
No error
Timeout
pevent is not a semaphore.
pevent is null.
Called from ISR
Amr Ali Abdel-Naby@2010
Introduction to uCOS-II V2.6
Signaling a Semaphore, OSSemPost
INT8U OSSemPost (OS_EVENT *pevent)
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pevent: A pointer to the semaphore to post to
Return value:
o
o
o
o
No error
Semaphore overflow
pevent is not a semaphore.
pevent is null.
Amr Ali Abdel-Naby@2010
Introduction to uCOS-II V2.6
Getting a Semaphore without Waiting,
OSSemAccept
INT16U OSSemAccept (OS_EVENT *pevent)
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•
pevent: A pointer to the semaphore to pend to
Return value:
o
o
Count
0 case of error or semaphore is no available
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)
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•
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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.
Amr Ali Abdel-Naby@2010
Introduction to uCOS-II V2.6
