embOS for Renesas M16C6x / M16C20 / R8C was developed for and with Tasking compiler and supports all memory models offered by this compiler. It comes with easy to use start projects for Tasking's EDE. Software development with Crossview Pro and Crossview Pro simulator simulator is supported.

Resources and performance data

Memory usage
Kernel size (ROM)	1680 bytes
Kernel RAM usage	29 bytes
RAM usage per task control block	17 bytes
RAM usage per resource semaphore	4 bytes
RAM usage per counting semaphore	2 bytes
RAM usage per mailbox	11 bytes
RAM usage per software timer	11 bytes
RAM usage event	0 bytes
Min. stack-size per task (RAM)	40 bytes
Timing
Context switch time	342 clock cycles (21.3 µs), independent of number of tasks
Interrupt latency time	max. 158 clock cycles (9.9 µs)
Kernel CPU usage/TICK	less than .4% of total calculation time at 1000 Interrupts/second (1ms TICK)
Basic time unit (TICK)	typ. 1 ms, min. 20 µs (50 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 timings given above were measured with embOS release build on an M30624 CPU running at 16MHz in SMALL memory model.

embOSView offers system analysis during runtime

Available Emulators

• Renesas
• HP

Additional information

Tasking Web site for additional compiler info / support
Renesas Web site for additional CPU info / support

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Release notes

Updated: 2004-07-16 [AW]
Updated: 2003-06-27 [AW]

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

Tool chain used for build

The following tools have been used:

TASKING Toolchain 3.0r1

Compiler:  TASKING CM16C   v3.0r1
Assembler: TASKING ASM16C  v3.0r1
Librarian: TASKING ARM16C  v3.0r1
Workbench: TASKING EDE v3.0

New features

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 3.10k

1. OS_GetMailTimed()
   New mailbox retreiving 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 format 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.

Version 3.06h

1. Modified for Tasking toolchain 2.1
2. All embOS interrupts now defined in RTOSInit.c
   An additional interrupt definition in assembler file is not required anymore. The RTOSVect.asm file is eliminated. Default UART for embOSView changed to UART0.

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 3.04i

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 3.10f

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

Version 3.06e

1. Context switching time improved
   Context switching time has been reduced to 373 clock cycles (23.3 us)
   (near model, M16C62 @16MHz)

Program corrections

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 3.06h

1. OS_Unuse error code corrected
   When calling OS_Unuse() more often than OS_Use(), the debug version generated an OS_ERR_TASKLIST_CORRUPT error instead of OS_ERR_UNUSE_BEFORE_USE.
   This problem exists in all previous embOS versions and is fixed with version 3.06h.

Version 3.04i

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

Version	Release date	Short explanation
V3.20g	16. Jul 2004	New embOS sources 3.20g, toolchain 3.0 supported
V3.10q	27. Jun 2003	New embOS sources 3.10q, toolchain 2.3 supported
V3.06h	23. Nov 2001	New version for toolchain 2.1
V3.06e	21. Sep 2001	New version with trace functionality
V3.04	01. Feb 2001	First version with release history

Miscellaneous

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