1. Tool chain used for build
2. Performance
3. New features
4. Improvements
5. Program corrections
6. Known problems
7. Release history
8. Miscellaneous

Tool chain used for build

The following tools have been used:

Compiler:  Renesas NC30  Version 5.43.0
Assembler: Renesas AS30  Version 5.14.0
Librarian: Renesas LB30  Version 1.02.0
Workbench: Renesas HEW   Version 4

Performance

1. Task switch time

Near memory model: 32.6 us = 523 cycles
Far memory model: 52.9 us = 847 cycles

2. Interrupt latency for Fast interrupt
   Near memory model: 3.2 us = 51 cycles
   Far memory model: 3.9 us = 63 cycles

Absolute timings are based on an M16C/62 running at 16 MHz

New features

Version 3.32o

1. Automatic call of OS_INIT_SYS_LOCKS() removed.
   During initialization of embOS, OS_INIT_SYS_LOCK() is not called automatically.
   As most of the applications do not need thread safe system libraries, an automatic activation of syslocks causes unwanted overhead.
   If supported and required, the user may call OS_INIT_SYS_LOCKS() from his own application after normal initialization of embOS.
   

Version 3.32m

1. OS_TimerEx, Extended timer implemented
   Extended timers are software timers which call a user defined callback function when the timer expires.
   In comparison to normal embOS timers, a parameter is passed to the timer callback function.
   The parameter value is initialized during timer creation.

Version 3.32j

1. OS_CSemaRequest implemented
   May be used to decrement a counting semaphore conditionally, if a signal is available.
   The function never blocks the calling task and delivers a result which indicates whether the semaphore was available.

Version 3.32g

1. Add start project for MSC MODSDKM16/CM16C62P board

Version 3.32f

1. OS_INIT_SYS_LOCKS() implemented
   May be used to include initialization code for thread safe system libraries automatically.
   If defined, this new function is called from OS_IntKern().

Version 3.32d

1. OS_Q_GetPtrTimed() implemented
   New queue retrieval function which waits for a message with specified timeout.

Version 3.32c

1. OS_EVENT_WaitTimed() implemented
   New event object function to wait for an event with a timeout limit.

Version 3.32b

1. Task context modified for debug builds
   The number of task activations is now part of the task context in debug builds.
   The number of activations are therefore displayed in the task list window of embOS plugin, when an embOS debug library is used.
   Previous versions of embOS showed this information in profiling builds only.

Version 3.32a

1. A parameter may be passed to a task function
   Using the new embOS functions OS_CREATETASK_EX() or OS_CreateTasEx() allows to pass a void pointer as parameter to a task.

Version 3.32

1. Event objects introduced
   Event objects are standalone objects which are not assigned to a specific task.
   Event objects may be used to synchronize one or multiple task to a specific event.
   Events can be triggered from a task, a timer, or an interrupt handler.

Version 3.30a

1. embOS internal time handling modified to allow long delays
   For 8- and 16-bit CPUs the maximum range for delays and timer periods is limited to 32767 embOS timer ticks, because time comparison ist done by integer calculation.
   By recompiling sources with datatype OS_TIME defined as signed long, longer delays and timer periods up to 2147483647 ticks can be realized.
   The embOS libraries of object version are still delivered with the limitation to 32767 timer ticks.

Version 3.28p

1. New error handling for version without round robin scheduling
   In debug versions of embOS, OS_Error() is called with error code OS_ERR_TASK_PRIORITY, if a task is created with a priority which is already assigned to an other task.
   OS_Error() is also called with the same errorcode, if a task priority is assigned by call of OS_SetPriority() and the new pririty is already assigned to an other task.
   Round robin switching can be disabled by recompiling sources with OS_RR_SUPPORTED defined as 0.

Version 3.28l

1. OS_SignalCSemaMax()
   New counting semaphore handling function which specifies a maximum count value.
   This allows counting semaphores used as binary semaphores.

Version 3.28i

1. OS_DeleteRSema()
   New resource semaphore handling function allows to delete resource semaphores during runtime.
   

Version 3.28h

1. Additional error checks in debug builds of embOS
   OS_CreateRSema() now generates an error, when the addressed resource semaphore was already created before.
   OS_CreateCSema() now generates an error, when the addressed counting semaphore was already created before.
   OS_CreateMB() now generates an error, when the mailbox was already created before.
   OS_CreateTimer() now generates an error, when the software timer was already created before.
   OS_MEMF_Create() now generates an error, when the addressed fixed size memory pool was already created before.

Version 3.28g

1. OS_GetSuspendCnt()
   New info function to examine suspension state and count of a task.

Version 3.26

1. OS_Terminate() modified
   Tasks may be terminated anytime, regardless of task state.
   All resources claimed by the terminated task are automatically released.

Version 3.22a

1. OS_PutMailFront() / OS_PutMailFront1
   New mailbox functions to enable LIFO behavior of mailboxes.
2. OS_PutMailFrontCond() / OS_PutMailFrontCond1()
   New conditional mailbox functions to enable LIFO behavior of mailboxes.

Version 3.20

1. OS_Suspend() / OS_Resume() implemented
   New functions to suspend and resume tasks unconditionally.
2. Fixed size memory blocks implemeted
   New functions to allocate fixed size memory blocks from embOS.
3. Dynamic memory allocation supported by embOS
   Thread safe dynamic memory allocation functions implemented.

Version 3.10p

1. Fast interrupt mode introduced
   Inside embOS, interrupts are not disabled. Interrupt priority is raised to level 4 instead.
   This enables high speed interrupt processing with very short interrupt latency for interrupts running at priorities above 4.
   This mode is default in all delivered libraries and can only be changed by recompiling embOS sources.

Version 3.10k

1. OS_GetMailTimed()
   New mailbox retrieving function with timeout.

Version 3.10e

1. New info functions
   OS_GetpCurrentTask() to identify the running task.
   OS_GetpCurrentTimer() to identify the timer whos callback is actually running.

Version 3.10

1. OS_WaitSingleEvent()
   Unmasked events remain unchanged, when function returns.
2. OS_WaitSingleEventTimed()
   Unmasked events remain unchanged, when function returns. Timeout for waiting can be specified.
3. embOSView data transfer protocol modified
   New data format requires embOSView version 3.10 or later.

Version 3.08a

1. Message Queue functionality enhanced
   OS_Q_GetPtrCond() function enables conditional request of data from Queue without task suspension.
   OS_Q_GetMessageCnt() functions delivers number of messages in the queue.

Version 3.08

1. Message Queues
   Message queues enable intertask communication with messages of various size.

Version 3.06h

1. Renesas ROM monitor KD30 supported per default
   Now the distibution of embOS is configured for use of KD30 per default. Therefore the startup file ncrt30.a30 and the vector definition file sect30.inc are modified.
   To enable KD30 support, which uses UART1 for communication, the default setting of UART for embOSView was changed to UART0 in RTOSInit.c.

Version 3.06f

1. OS_Use now returns a value
   When using a resource semaphore with a call of OS_Use(), the actual usage counter of the requested semaphore is returned as integer value. This may be helpful for some applications and is a lot more efficient than calling OS_Use() and then check the usage counter by calling OS_GetSemaValue().

Version 3.06

1. Serial interface for embOSView shared with application
   The serial interface used for communication with embOSView is now available for the application.
   embOSView can serve as a terminal for the target application in parallel with trace and profiling over the same serial interface.
   The user application can call the new function OS_SendString() to send data to the terminal, OS_SetRxCallback() to set a callback function for received characters.
2. Trace build added
   embOS can be traced during runtime with embOS Viewer version 3.06.
   This allows monitoring of the API functions and their parameters called by the application.
   Task- and API-specific filters can be defined via embOSView or directly by the application program via new API calls.
   This functionality requires the trace build (NT, MT, FT or HT libraries)
3. New event function
   OS_WaitEventTimed() implemented to handle timeout conditions during waiting for events.
4. New info function
   OS_IsTask() implemented to check, whether task actually exists.

Version 3.04r

1. Support for embOSView
   embOS Viewer can communicate with embOS via UART if the MCU is properly initialized and the required interrupt routines are present. (Default is UART 1, 38400 baud). This can be easily changed in RTOSInit.c
   embOSView is now shipped with the software.
2. Profiling
   New profiling builds allow measurement of task execution times.
3. Improved support for nested interrupt
   OS_EnterNestableInterrupt(), OS_LeaveNestableInterrupt() defined.
4. New timer functions introduced
   OS_SetTimerPeriod(),OS_GetTimerPeriod() introduced, to modify / check reload value of timer.
   OS_GetTimerStatus() introduced to check whether timer is active.
   OS_GetTimerValue() introduced to check remaining time of timer.
5. Additional functions
   OS_SetTimeSlice() added to modify the timeslice of a task during runtime.
   OS_CreateCSema() modified; now an initial value of sema can be set.
6. Modified functions
   OS_ClearEvent() now returns the actual state of events before clearing.

Improvements

Version 3.32i

1. Task switch to OS_Idle() modified.
   The call of OS_Idle() from OS_ChangeTask can be overwritten (inhibited) by defining the macro OS_IDLE() which is norammly defined as OS_Idle().
   This allows task switching via an exception for specific CPU/compiler versions.

Version 3.32g

1. Pointer comparison improved for fixed size memory pools (OS_MEMF module).
   Some compiler produced wrong pointer comparison code in far memory model.
   For specific CPU/compiler versions, the new OS_POINTER_TO_VALUE() function was inroduced to deliver correct results in pointer comparison.

Version 3.28n

1. embOS round-robin scheduling may be disabled.
   Round-robin scheduling may be disabled by recompiling sources with OS_RR_SUPPORTED defined as 0.
   This will save some bytes of RAM and ROM and may make sense for small CPUs.

Version 3.28g

1. embOS scheduling simplified
   Task activation and deactivation on "waitable objects" as mailboxes, semaphores, events, fixed size memory blocks now all use the same scheduling method.
   This modification saves ROM and RAM and makes scheduler easier to understand and to maintain.
   Applications which accessed internal data structures of waitable objects directly have to be modified.

Version 3.10p

1. Fast interrupt mode introduced
   Inside embOS, interrupts are not disabled. Interrupt priority is raised to level 4 instead.
   This enables high speed interrupt processing with very short interrupt latency for interrupts running at priorities above 4.
   

Version 3.10f

1. Memory requirements reduced
   Granularity enhanced for non embOSView builds to save ROM and RAM

Version 3.04r

1. Context switching time improved
   Context switching time has been reduced to 24.5 us
   (near model, M16C62 @16MHz)
2. Interrupt latency time reduced
   Interrupt latency times have been reduced to better than 8.0 us
   (near model, M16C62 @16MHz)

Program corrections

Version 3.32o

1. OS_Unuse() corrected
   OS_Unuse() must not be called from a task that does not claim the resource semaphore.
   According to the documentation, the debug build of embOS should generate a call to OS_Error() if this fault happens.
   All previous versions of embOS did not call OS_Error(). Now, OS_Error() will be called in that situation with error code 156: OS_ERR_RESOURCE_OWNER().

Version 3.32l

1. OS_EVENT_Delete() corrected
   OS_EVENT_Delete() did not work correctly. OS_LeaveRegion() was called inside the function without calling OS_EnterRegion() bfore.
   In debug builds of embOS, the error handler OS_Error() was called with error 151 (OS_ERR_LEAVEREGION_BEFORE_ENTERREGION).
   In release builds the system was blocked because the underflow of region count inhibts all further task switches, or system crashes, because incrementing the region count the next time allows task switches instead of blocking them. The problem existed in all previous versions and is fixed with version 3.32l.
2. Round-robin task switching corrected.
   Round robin task switching did not work correctly in previous version. A task which was blocked for some reason could be activated. The system crashed during task switch.
   The problem existed since version 3.32j and is fixed with version 3.32l.

Version 3.32k

1. Handler function _OS_OnTx() for serial communication to embOSView corrected.
   The transmission handler for communication with embOSView might have sent incorrect data to embOSView, because internal control state was updated after sending the data.
   The problem occured on a new embOS port for a specific CPU only and is fixed with version 3.32k.
   

Version 3.32h

1. OS_Error() was required in release build when resource semaphores were used.
   When using release build libraries and resource semaphores, the embOS error handler OS_Error() was required and the file OS_Error.c had to be compiled and linked in a project.
   The problem existed since version 3.28i of embOS and is fixed with version 3.32h.

Version 3.32e

1. OS_GetMessageCnt() corrected.
   The type of the retun value of OS_GetMessageCnt() was an unsigned integer in release builds, but an integer in debubg builds.
   This was corrected to return an unsigned integer in all builds.
   The problem existed in all previous versions of embOS end is fixed with version 3.32e.

Version 3.32a

1. embOSView corrected.
   embOSView sometimes showed wrong task state "Terminated" for tasks which were not terminated.
   This bug existed in all previous versions of emBOSView and is fixed with version 3.32a.

Version 3.30d

1. OS_MEMF_Create() corrected.
   Alignment check of buffers for fixed size memory blocks did not work correctly in debug libraries of embOS.
   OS_Error() was called during OS_MEMF_Create(), even though the memory pool buffers start address was correctly aligned.
   This problem existed since embOS version 3.28m in all debug build libraries and is fixed with version 3.30d.

Version 3.30b

1. OS_Suspend() corrected.
   OS_Suspend() did not work correctly, when an activated task with higher priority than the running task was suspended.
   When the task with highest priority was suspended during system initialization before embOS was started, embOS crashed during the call of OS_Start(), or called the embOS error handler OS_Error() with error code OS_ERR_INV_TASK (128).
   The same crash occured, when the application was running in a critical region and a task with higher priority was activated, but not started because of the critical region, and was then suspended by a call of OS_Suspend().
   This problem existed in all previous embOS versions and is fixed with version 3.30b.

Version 3.28q

1. Problem with suspended tasks which were on delay fixed.
   If a task which was on delay was suspended, the delay timer for that task was not handled.
   This might have resulted in additional longer delay when the task was resumed later.
   This problem existed in all previous embOS versions and is fixed with version 3.28q.

Version 3.28p

1. OS_Suspend() corrected.
   OS_Suspend() did not work corretly, when the current task was suspended from within an interrupt handler, or from a critical region.
   The application crashed, or called the embOS error handler OS_Error() with error code OS_ERR_INV_TASK (128).
   As OS_Suspend() automatically enters a critical region in debug-trace builds, OS_Suspend() also failed, when it was called to suspend the current task in debug-trace builds of embOS.
   This problem existed in all previous embOS versions and is fixed with version 3.28p.

Version 3.28m

1. Alignment problems fixed for fixed size memeory blocks
   Some CPUs, mainly the 32bit RISC types, require aligned buffer start addresses for fixed size memory pools.
   The debug version of embOS now checks alignment of buffer start address and data blocks in the buffer. If data blocks and biffer start address is not aligned, an error is generated and embOS error handler is called during creation of a fixed size memory pool.
   This problem existed in all previous embOS versions and is fixed with version 3.28m.

Version 3.28l

1. OS_MEMF_Free() added
   The function OS_MEMF_Free() was not included in embOS libraries, but was documented in embOS users manual and was also declared in RTOS.h.
   This problem existed in all previous embOS versions and is fixed with version 3.28l.

Version 3.28k

1. OS_MEMF_IsInPool() corrected
   OS_MEMF_IsInPool() failed, if a pointer was checked which pointed to the first address after the memory pool. This pointer was reported as belonging to the pool.
   This problem existed in all previous embOS versions and is fixed with version 3.28g.

Version 3.28g

1. OS_WakeTask() for trace build corrected
   OS_WakeTask() in trace build disabled task switches.
   This problem existed since version 3.24 and is fixed with version 3.28g.
2. OS_WaitCSemaTimed() corrected
   Semaphore handling was changed with embOS sources version 3.26.
   Unfortunately,during call of OS_WaitCSemaTimed() an internal control counter was decremented twice, which resulted in wrong control state of semaphore. Overflow of this counter caused, that the calling task remained suspended until the timeout expired, even though, the semaphore was signaled.
   This problem existed in version 3.26 only and is fixed with version 3.28g.
3. OS_GetMailTimed() / mailbox handling corrected
   During call of OS_GetMailTimed, interrupts were re-enabled too early. If a mail was just put into a mailbox and the timeout occured at the same time, a mailbox internal control variables which managed waiting tasks was set to a wrong value.
   This resulted in wrong mailbox handling and caused task waiting for mail kept suspended, even though, mail was available. This problem existed in all previous versions of embOS and is fixed with version 3.28g.

Version 3.26a

1. OS_MEMF_Release() corrected
   OS_MEMF_Release() might have failed according to absolute address of memory block.
   The problem occured because address calculation was done with 16bit interger value.
   Calculation was modified to use 32bit values to fix the problem.

Version 3.20c

1. OS_GetMailTimed() corrected
   OS_GetMailTimed () did not retrieve a mail after 256 calls, the waiting task remained suspended. Corrected with version 3.20c of embOS.
   This problem exists in all previous embOS versions and is fixed with version 3.20c.

Version 3.10p

1. GetMail functions corrected
   Internal functions for retrieving mail from a mailbox did not disable interrupts. This could cause message losses, when mail was written into mailboxes from within interrupt handlers.
   This problem exists in all previous embOS versions and is fixed with version 3.10p.

Version 3.10i

1. OS_SendString() corrected
   When calling OS_SendString() with UART for embOSView disabled, the system was blocked. This problem exists in all previous embOS versions 3.10 and is fixed with version 3.10i.

Version 3.06f

1. Round robin switch bug corrected
   Round robin task switch caused system malfunction when a higher prioritized task was activated from within an interrupt just the moment one of the round robin tasks was deactivated at the end of its time slice.
   This problem exists in all previous embOS versions and is fixed with version 3.06f.

Version 3.06e

1. Task switch from interrupt corrected
   Multiple interrupts performing a taskswitch from within the interrupt handler caused a system malfunction. Further taskswitches were blocked. This error is corrected with version 3.06e.

Version 3.06b

1. Trace functions defined in RTOS.h
   Some of the new trace functions were not defined in RTOS.h. This could result in warnings, when those functions were called from user application.

Version 3.06a

1. Task switch from interrupt fixed
   Task switch from user defined interrupt routine did not work, when interrupt routine used local variables.

Version 3.04r

1. Modified functions
   OS_StartTimer() changed to match doc exactly.
   OS_GetMailCond() had assertions which did not permit usage in interrupt or software timers (debug build only). Fixed.

Known problems

None

Release history

Miscellaneous

This document was first released with version 3.04r of the software.
Software released earlier is documented internally.
This information is available at request.