Wednesday, February 16, 2011


This is the fifth and the last post about the comparison between uCOS-II and uCOS-III. The whole five posts can serve as a guide for migrating from uCOS-II to uCOS-III.

In this post, I will try to summarize the API changes themselves. I wont go in the details of the APIs' arguments but I will try to hint the differences on a higher level. Changes in APIs were aiming at having more consistent code.

Changes in Critical Sections
Macros defined to control a critical section are redefined and moved to CPU.H.

General Changes in APIs
  • Accept APIs are removed. They are now built in Pend APIs.
  • Naming APIs are removed. Names are defined during Creation APIs.
  • Posting APIs are combined into a single API where all options are built in a single Post API.
  • The type OS_EVENT is no longer used. Instead new types were added.
  • Query APIS are removed because they are rarely used.
  • All object handles should be created by the application prior to its creation. Number of objects are no more defined during compilation.
Changes in Event Flags APIs
Changed APIs are OSFlagCreate, OSFlagDel, OSFlagPend, OSFlagPendGetFlagsRdy, and OSFlagPost.

Changes in Message Mailboxes APIs
No direct implementation of message mailboxes APIs. You can view a mailbox as a message queue with a single message. Thus, message queues APIs are used to emulate message mailboxes APIs.

Changes in Memory Management APIs
Changed APIs are OSMemCreate, OSMemGet, and OSMemPut.

Changes in Mutual Exclusion Semaphores APIs

Changed APIs are OSMutexCreate, OSMutexDel, OSMutexPend, and OSFlagPost. OSMutexPendAbort is added in uCOS-III.

Changes in Message Queues APIs

Changed APIs are OSQCreate, OSQDel, OSQPend, OSQPost, and OSQPendAbort.

Changes in Semaphores APIs

Changed APIs are OSSemCreate, OSSemDel, OSSemPend, OSSemPost, OSSemPendAbort, and OSSemSet.

Changes in Task Management APIs

Changed APIs are OSTaskChangePrio, OSTaskCreate, OSTaskDel, OSTaskResume, OSTaskRegGet, OSTaskRegSet, OSTaskSuspend, and OSTaskStkChk.
Removed APIs, others than mentioned above in the general changes section, are OSTaskDelReq, and OSTaskCreateExt.
Added APIs are OSTaskQFlush, OSTaskQPend, OSTaskQPendAbort, OSTaskQPost, OSTaskSemPend, OSTaskSemPendAbort, OSTaskSemPost, OSTaskSemSet, and OSTaskTimeQuantaSet.

Changes in Time Management APIs

All APIs are changed.

Changes in Timer Management APIs

All APIs are changed except for OSTmrSignal is removed.

Changes in Miscellaneous APIs

Changed APIs are OSInit, OSSchedLock, OSSchedUnlock, and OSVersion.
Changed and renamed APIs are OSPendMulti, and OSStatTaskCPUUsageInit.
Added APIs are OSSchedRoundRobinCfg, and OSSchedRoundRobinYield.

Changes in Hook and Port APIs

Changed APIs are OSTaskStkInit, OSTaskCreateHook, and OSTaskDelHook.
Changed and/or renamed APIs are OSInitHook, OSIdleTaskHook, and OSStatTaskHook.
Added APIs are OSGetTS, and OSTaskReturnHook.
Deleted APIs are OSInitHookEnd, and OSTCBInitHook.

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