M32C/M16C80, NC308

embOS for Renesas M16C80 / M32C was developed for and with Renesas NC308 compiler and supports all memory models offered by this compiler. It comes with easy to use start projects for Renesas HEW V4. Software development with PD308 debugger, KD308- or KD3083-ROM-Monitor, PD308 simulator or HEW M32C simulator is supported.

Resources and performance data

Memory usage
Kernel size (ROM)	1434 bytes
Kernel RAM usage	37 bytes
RAM usage per task control block	27 bytes
RAM usage per resource semaphore	6 bytes
RAM usage per counting semaphore	2 bytes
RAM usage per mailbox	13 bytes
RAM usage per software timer	13 bytes
RAM usage event	0 bytes
Min. stack-size per task (RAM)	50 bytes
Timing
Context switch time	416 clock cycles (20.8 µs), independent of number of tasks
Interrupt latency time	max. 164 clock cycles (8.2 µs)
Kernel CPU usage/TICK	less than .3% of total calculation time at 1000 Interrupts/second (1ms TICK)
Basic time unit (TICK)	typ. 1 ms, min. 10 µs (100 kHz interrupt frequency)
Features
Max. no. of tasks	Unlimited (by available RAM only)
Max. no. of mailboxes	unlimited (by available RAM only)
Max. no. of semaphores (resource/binary/counting)	unlimited (by available RAM only)
Max. no. of software timers	unlimited (by available RAM only)
Max. no. of priorities	255
Stack size idle task (RAM)	0(no memory needed)
Nested interrupts	permitted
Task switches from within ISR	possible

Absolute data given above were measured with embOS release build on an M30803FG CPU running at 20MHz in NEAR memory model.

embOSView offers system analysis during runtime

Available Emulators

• Renesas

Additional information

Renesas Web site for additional CPU / compiler info

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Release notes

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

Tool chain used for build

The following tools have been used:

Compiler:  RENESAS  nc308 V5.40
Assembler: RENESAS  as308 V4.02
Librarian: RENESAS  lb308 V2.02.01
Workbench: RENESAS  HEW   V4.00.03

Performance

embOS for M32C supports M16C80 CPU's as well as M32C CPU's

1. Task switch time (Near memory model, Release build): 20.8 us = 416 cycles
2. Interrupt latency (Near memory model, Release build): 10.6 us = 211 cycles
3. Fast Interrupt latency (Near memory model, Release build): 1.3 us = 26 cycles

Absolute timings are based on 20MHz CPU clock

New features

Version 3.32j

1. OS_CSemaRequest implemented
   May be used to decrement a caounting semaphore, 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. 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 from 5 to 7.
   This mode is default in all delivered libraries and can only be changed by recompiling embOS sources.
   Existing application software has to be adapted, if interrupt handler running at priorities above 4 use embOS functions.
2. Projects for HEW V4 delivered with embOS
   embOS for M32C/M16C80 now comes with projects and workspaces for Renesas HEW 4.
   Projects for the older toolmanger are not delivered anymore.
3. Updated to compiler version 5.40
   embOS for M32C/M16C80 was updated to be used with compiler version 5.40.
   Earlier versions of embOS libraries might not run with new runtime libraries.

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 versions for 8- and 16-bit CPUs 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 priority 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.
4. Byte aligned objects supported by embOS
   Since version 3.20, libraries for byte aligned objects are included in standard distribution.
5. Near constants supported by embOS
   Since version 3.20, libraries for near constants are included in standard distribution. These libraries are required for R8C CPU

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 3.10d

1. OS_GetpCurrentTimer()
   New info routine. May be used in timer callback routines to examine which timer expired.
2. OS_GetpCurrentTask()
   New info routine. May be used to examine current running task.

Version 3.10

1. Data format for communication with embOSView modified
   For terminal I/O in embOSView, the data farmat was changed. Therefore embOSView V3.10 or later is required.
2. OS_WaitSingleEvent()
   Unmasked events remain unchanged when function returns.
3. OS_WaitSingleEventTimed()
   Unmasked events remain unchanged when function returns. Timeout for waiting can be specified.

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.

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 3.24

1. Stack check performance increased
   Stack check now runs much faster on 32- and 16-bit target CPUs.

Program corrections

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 correctly, 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.

1. Alignment problems fixed for fixed size memory 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 buffer 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_FreeBlock() added
   The function OS_MEMF_FreeBlock() 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_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.
   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.

Known problems / limitations

All versions

1. -fConst_not_ROM option not supported

Release history

Version	Release date	Short explanation
V3.32f	01. Mar 2007	Upgraded to embOS sources V3.32f
V3.32g	05. Jan 2007	Updated to compiler version 5.40. FAST interrupts implemented. Upgraded to embOS sources V3.32g
V3.28h	02. Sep 2005	Upgraded to embOS sources V3.28h
V3.24b	05. Jul 2005	Upgraded to embOS sources V3.24b
V3.08	09.April.2002	First release for Renesas NC308 compiler

Miscellaneous

This document was first released with version 3.08 of the software.
Software released earlier is documented internally.
This information is available at request.