Ucos-11
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UCOS-11 Real Time Operating System
μC/OS-II Initialization • A requirement of μC/OS-II is that you call OSInit() before you call any of its other services. OSInit() initializes all of μC/OSII’s variables and data structures • OSInit() creates the idle task (OSTaskIdle()) which is always ready-torun.
• Disabling and enabling interrupts through the two macros OS_ENTER_CRITICAL() and OS_EXIT_CRITICAL(), respectively. You use these macros when two tasks or a task and an ISR need to share data. • An ECB can either be a semaphore, a message mailbox or a message queue
Semaphores • mC/OS-II's semaphores consist of two elements: a 16-bit unsigned integer used to hold the semaphore count (0..65535), and a list of tasks waiting for the semaphore count to be greater than 0.
• if the semaphore allows your application to obtain any one of ‘n’ identical resources then, you would initialize the semaphore to ‘n’. The semaphore would then be used as a counting semaphore. • If you use the semaphore to signal the occurrence of one or more events then you would typically initialize the semaphore to 0.
• If you use the semaphore to access a shared resource then you would initialize the semaphore to 1 (i.e. use it as a binary semaphore).
five services to access semaphores: • • • • •
OSSemCreate() OSSemPend() OSSemPost() OSSemAccept() OSSemQuery().
Message Mailboxes • To enable μC/OS-II’s message mailbox services, you must set the configuration constant OS_MBOX_EN to 1 (see file OS_CFG.H).
• • • • •
OSMboxCreate() OSMboxPend() OSMboxPost() OSMboxAccept() OSMboxQuery()
Memory Management
μC/OS-II Initialization • A requirement of μC/OS-II is that you call OSInit() before you call any of its other services. OSInit() initializes all of μC/OSII’s variables and data structures • OSInit() creates the idle task (OSTaskIdle()) which is always ready-torun.
• Disabling and enabling interrupts through the two macros OS_ENTER_CRITICAL() and OS_EXIT_CRITICAL(), respectively. You use these macros when two tasks or a task and an ISR need to share data. • An ECB can either be a semaphore, a message mailbox or a message queue
Semaphores • mC/OS-II's semaphores consist of two elements: a 16-bit unsigned integer used to hold the semaphore count (0..65535), and a list of tasks waiting for the semaphore count to be greater than 0.
• if the semaphore allows your application to obtain any one of ‘n’ identical resources then, you would initialize the semaphore to ‘n’. The semaphore would then be used as a counting semaphore. • If you use the semaphore to signal the occurrence of one or more events then you would typically initialize the semaphore to 0.
• If you use the semaphore to access a shared resource then you would initialize the semaphore to 1 (i.e. use it as a binary semaphore).
five services to access semaphores: • • • • •
OSSemCreate() OSSemPend() OSSemPost() OSSemAccept() OSSemQuery().
Message Mailboxes • To enable μC/OS-II’s message mailbox services, you must set the configuration constant OS_MBOX_EN to 1 (see file OS_CFG.H).
• • • • •
OSMboxCreate() OSMboxPend() OSMboxPost() OSMboxAccept() OSMboxQuery()
Memory Management
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