embOS for NEC 78K4 series CPUs and IAR compiler

embOS for NEC 78K4 series was developed for and with IAR's compiler and by now supports the large memory model offered by this compiler. It comes with an easy to use start project for IAR's embedded workbench. Software development with NEC debugger, simulator and CSpy simulator is supported.

Resources and performance data

Memory usage
Kernel size (ROM)	1401 bytes
Kernel RAM usage	31 bytes
RAM usage per task control block	22 bytes
RAM usage per resource semaphore	5 bytes
RAM usage per counting semaphore	2 bytes
RAM usage per mailbox	12 bytes
RAM usage per software timer	11 bytes
RAM usage event	0 bytes
Min. stack-size per task (RAM)	120 bytes
Timing
Context switch time	142 µs, independent of number of tasks
Interrupt latency time	better 56 µs
Kernel CPU usage/TICK	less than 1% of total calculation time at 1000 Interrupts/second (1ms TICK)
Basic time unit (TICK)	typ. 1 ms, min. 100 µs (10 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	256
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 78K4 CPU running at 16MHz in LARGE memory model.

embOSView offers system analysis during runtime

Available Emulators

Additional information

Release Notes embOS 78K4 for IAR compiler
IAR Web site for additional compiler info / support