Introduction to uCOS II v2 6 m8

Introduction to uCOS-II V2.6 About SwiftACT • A Technology services startup company o 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: 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 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 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 Message Mailboxes • A message mailbox is a μC/OS-II object that allows a task or an ISR to send pointersized variable to another task OSMboxCreate() OSMboxPost() Task OSMboxPend() OSMboxAccept() OSMboxQuery() Task ISR OSMboxPost() OSMboxAccept() Amr Ali Abdel-Naby@2010 Introduction to uCOS-II V2.6 Message Creating a Mailbox, OSMboxCreate OS_EVENT *OSMboxCreate (void *msg) • msg: A pointer to a message to deposit in the mailbox o o • If null, mailbox is empty & used to signal occurrence of events If ! null, mailbox is used to access shared resources 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 Mailbox, OSMboxDel OS_EVENT *OSMboxDel (OS_EVENT *pevent, INT8U opt, INT8U *err) • • pevent: A pointer to the mailbox to be deleted opt: Delete options o o • 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 mailbox Amr Ali Abdel-Naby@2010 Introduction to uCOS-II V2.6 Deleting a Mailbox, OSMboxDel cont’d OS_EVENT *OSMboxDel (OS_EVENT *pevent, INT8U opt, INT8U *err) • Return value: Null if successful Amr Ali Abdel-Naby@2010 Introduction to uCOS-II V2.6 Waiting for a Message at a Mailbox, OSMboxPend void *OSMboxPend (OS_EVENT *pevent, INT16U timeout, INT8U *err) • • pevent: A pointer to the mailbox to pend to timeout: o o • err: o o o o o  wait for ever !0  wait with specific timeout No error Timeout pevent is not a mailbox pevent is null Called from ISR Amr Ali Abdel-Naby@2010 Introduction to uCOS-II V2.6 Sending a Message to a Mailbox, OSMboxPost INT8U OSMboxPost (OS_EVENT *pevent, void *msg) • • • pevent: A pointer to the mailbox to post to msg: A pointer to the message to send Return value: o o o o o No error Mailbox is full pevent is not a mailbox pevent is null Posting a null pointer Amr Ali Abdel-Naby@2010 Introduction to uCOS-II V2.6 Sending a Message to a Mailbox, OSMboxPostOpt INT8U OSMboxPostOpt (OS_EVENT *pevent, void *msg, INT8U opt) • • OSMboxPostOpt = OSMboxPost + options opt: o o Post to a single waiting task Post to all tasks waiting Amr Ali Abdel-Naby@2010 Introduction to uCOS-II V2.6 Getting a Message without Waiting, OSMboxAccept void *OSMboxAccept (OS_EVENT *pevent) • • pevent: A pointer to the mailbox to pend to Return value: o o !Null  Message received Null  Case of error or mailbox is empty Amr Ali Abdel-Naby@2010 Introduction to uCOS-II V2.6 Obtaining the Status of a Mailbox, OSMboxQuery INT8U OSMboxQuery (OS_EVENT *pevent, OS_MBOX_DATA *pdata) • • • pevent: A pointer to the desired mailbox pdata: A pointer to the returned mailbox information Return value: o o o No error pevent is not a mailbox pevent is null Amr Ali Abdel-Naby@2010 Introduction to uCOS-II V2.6 Using a Mailbox as a Binary Semaphore OS_EVENT *MboxSem; void Task (void *pdata){ INT8U err; for (;;) { OSMboxPend(MboxSem, 0, &err); /* Obtain access to resource */ /* Task has semaphore, access resources */ OSMboxPost(MboxSem, (void*)1); /* Release access to resource */ } } Amr Ali Abdel-Naby@2010 Introduction to uCOS-II V2.6 Using a Mailbox Instead to Signal Occurrence of Events OS_EVENT *MboxTimeDly; void Task1(void *pdata){ INT8U err; for (;;) { OSMboxPend(MboxTimeDly, timeout, &err); /* Wait for event */ /* Code after time delay */ } } void Task2(void *pdata){ INT8U err; for (;;) { OSMboxPost(MboxTimeDly, (void *)1); /* Signal event */ } } Amr Ali Abdel-Naby@2010 Introduction to uCOS-II V2.6 [...]... Abdel-Naby@2010 Introduction to uCOS- II V2. 6 Waiting for a Message at a Mailbox, OSMboxPend void *OSMboxPend (OS_EVENT *pevent, INT16U timeout, INT8U *err) • • pevent: A pointer to the mailbox to pend to timeout: o o • err: o o o o o 0  wait for ever !0  wait with specific timeout No error Timeout pevent is not a mailbox pevent is null Called from ISR Amr Ali Abdel-Naby@2010 Introduction to uCOS- II V2. 6 Sending... Message to a Mailbox, OSMboxPost INT8U OSMboxPost (OS_EVENT *pevent, void *msg) • • • pevent: A pointer to the mailbox to post to msg: A pointer to the message to send Return value: o o o o o No error Mailbox is full pevent is not a mailbox pevent is null Posting a null pointer Amr Ali Abdel-Naby@2010 Introduction to uCOS- II V2. 6 Sending a Message to a Mailbox, OSMboxPostOpt INT8U OSMboxPostOpt (OS_EVENT... OSMboxPostOpt = OSMboxPost + options opt: o o Post to a single waiting task Post to all tasks waiting Amr Ali Abdel-Naby@2010 Introduction to uCOS- II V2. 6 Getting a Message without Waiting, OSMboxAccept void *OSMboxAccept (OS_EVENT *pevent) • • pevent: A pointer to the mailbox to pend to Return value: o o !Null  Message received Null  Case of error or mailbox is empty Amr Ali Abdel-Naby@2010 Introduction. .. Ali Abdel-Naby@2010 Introduction to uCOS- II V2. 6 Obtaining the Status of a Mailbox, OSMboxQuery INT8U OSMboxQuery (OS_EVENT *pevent, OS_MBOX_DATA *pdata) • • • pevent: A pointer to the desired mailbox pdata: A pointer to the returned mailbox information Return value: o o o No error pevent is not a mailbox pevent is null Amr Ali Abdel-Naby@2010 Introduction to uCOS- II V2. 6 Using a Mailbox as a Binary Semaphore... *MboxSem; void Task (void *pdata){ INT8U err; for (;;) { OSMboxPend(MboxSem, 0, &err); /* Obtain access to resource */ /* Task has semaphore, access resources */ OSMboxPost(MboxSem, (void*)1); /* Release access to resource */ } } Amr Ali Abdel-Naby@2010 Introduction to uCOS- II V2. 6 Using a Mailbox Instead to Signal Occurrence of Events OS_EVENT *MboxTimeDly; void Task1(void *pdata){ INT8U err; for (;;)... &err); /* Wait for event */ /* Code after time delay */ } } void Task2(void *pdata){ INT8U err; for (;;) { OSMboxPost(MboxTimeDly, (void *)1); /* Signal event */ } } Amr Ali Abdel-Naby@2010 Introduction to uCOS- II V2. 6