Embedded Real Time Kernel for Micros

In AVR/html/index.html the source documentation is found, please read the wiki too.

To learn what a (R)eal (T)ime (K)ernel is please visit https://en.wikipedia.org/wiki/Real-time_operating_system

This is a Real Time Kernel with dynamic priorities for tasks and it allows cooperation of tasks or preemptive scheduling.

Each task has a priority and can decide to run or to suspend the cpu to others who are ready to run.

Overall principle ist "highest priority task always runs",

if no one is ready at a certain point of time the so called "idle task" wil be activated which only does one thing,

count up a variable in debug mode for measureing cpu free time ore do nothing (and save energy) in production code.

Until now this code is running on Atmel AVR and ARM Cortex Hardware, it is tested on Atmega2560/Atxmega384 and SAM21J18A specific (Atxmega in Simulator only).

The project directory subdir AVR/ holds the ATmega and ATxmega Atmelstudio project, gcc is the recommended compiler toolchain.

In SAMD21/ the Atmelstudio projekt for SAMD21 is found with its machine setup files and some test code.

The Z180/ directory holds old Zilog Z180 code without makefile because the commercial C compiler i used that time isn't available today. So the code could only be used as reference when porting to newer z80 derivates on gcc.

I didn't use the Atmel ASF because i don't want to blow up this project with things that are not necessary for this project.

If one wants to use ASF or some other frame work, please create a new project with that and add the eRTK dirs.

After setting up plls,clock and so on call these

eRTK_init();

eRTK_timer_init();

eRTK_go();

and the system should be started up, highest priority ready state task should be running.

Using a similar ATmega, ATxmega or Cortex M0+ or Mx CPU is possible too,

try to adopt the #defines to your machine type.

AT(x)mega special:

The code this time only supports machines with 24bit program counter, so only the ones with more than 128kB flash have a chance to run directly.

If the smaller ones should be supported a 16bit program counter option has to be implemented, mostly the context switch push() and pop() have to be adopted.