ANTIRTOS

No any RTOS needed, you will see...

ANTIRTOS is an ultra-lightweight, universal C++ library designed for task management in IoT and embedded applications. It is coded in a single, small file, making it incredibly easy to integrate into your projects. ANTIRTOS aims to deliver a robust, secure, and efficient library for task management. With its focus on modularity and scalability, ANTIRTOS is suitable for a variety of devices, from simple microcontrollers to complex embedded systems. It is developed especially for embedded systems where the complexity and overhead of an RTOS are not justified. This is an universal branch with dynamic memory (heap) allocation approach.

The modern version is avaliable here: ANTIRTOS_MODERN, it enhances simplicity in usage by leveraging the standard library (std) using tuples and static allocation. However, it is not supported on some platforms yet.

Benifits:

1. Interrupts kept fast and controllable, no blocking anymore.
2. Easy to debug and understand.
3. Get an easy way of multitasking.
4. No dummy waiting/blockings. Wait by doing!
5. No need to have a deal with critical sections/mutexes/semaphores, no tasks stack memory overflows. Keep your project based on straight forward architecture

Get rid of complexity!
Allow your MCU to perform many tasks while using a very small amount of microcontroller memory. Manage function pointer queues in a simple way by simply placing your tasks there and pulling them from a main loop. This approach allows you to keep interrupts fast and at the same time control multitasking in a simple and transparent way. Pass arguments to you function, they will be saved in separate queue and handled.

Let’s explain a bit on examples.

0. To start using the library - include the header:

#include <antirtos.h>

1. Create queues in an easy way

fQ F1(4); // first queue is 4 elements(function pointers) long
fQ F2(4); // second queue is 4 elements(function pointers) long
fQ F3(8); // third queue is 8 elements(function pointers) long
fQP<int32_t> F4(3); // third queue is 3 elements(function pointers)
		    // functions are receiving int32_t argument

2. Wherever you want, just push your function pointers (and arguments if they needed).

void button1Interrupt(){
	F1.push(Below used following functions); // void dealAssociatedButton1() – is your task for this button
}
  
void button2Interrupt(){
	F2.push(dealAssociatedButton2);         // void dealAssociatedButton2() – is your task for this button
	F2.push(secondDealAssociatedButton2);   // void secondDealAssociatedButton2() – 
                                                // is your second task for this button
}
void timer1ElapsedInterrupt(){
	F3.push(dealAssociatedTimer1);  // void dealAssociatedTimer1() – 
                                        // is your task for this timer1 event 
}
void timer2ElapsedInterrupt(){
	F4.push(dealAssociatedTimer2, yourIntArg);  // void dealAssociatedTimer2(int yourIntArg) – 
                                                // is your task for this timer2 event and the variable yourIntArg
                                                //  passed like an argument 
}

3. In the main loop:

void loop() {
  // put your main code here, to run repeatedly:
	F1.pull();
	F2.pull();
	F3.pull();
	F4.pull();
}

This is it. All the interrupts kept as fast as possible; all the task functions/procedures handled. If you need to wait, do the job:

while(!neededFlag){
	F1.pull();
	F2.pull();
}

Or to delay for some time? Utilize a function like:

void DelayOnF1(uint64_t delay){
	uint64_t targetTime = delay + millis();
	while(millis() < targetTime) 
		F1.pull();
}

An example:

digitalWrite(13, HIGH); 	// sets the digital pin 13 on
//delay(1000);  		//not needed any more
DelayOnF1(1000);		// wait by doing
val = analogRead(3);  		// read the input pin

If you need to pass several arguments – no problem, you may use your own class for a queue:

class testClass{        // it is not used here, just like example how you may pass complex argument to your functions in queue
  public:
    int array[10]={0,0,0,0,0,0,0,0,0,0};
    float argument = 0.0;
};
fQP<testClass> F2(10);

Instances of your class passed to functions must be of constant size.

Delayed functions

Do you need just to delay some function from execution? Do not wait any more! Initialize:

 del_fQ F5(8); // 'delayed' queue

put where you want (here example of 2 functions put into queue):

 F5.push_delayed(your_func_1, 1000); // function your_func_1() will be delayed for 1000 'ticks'
 F5.push_delayed(your_func_2, 2000); // function your_func_2() will be delayed for 2000 'ticks'

in main loop (or other periodic loop) just need to:

void loop() {
.......
F5.pull(); //execute in loop just this super fast function;
}

in some timer or periodic function:

  F5.tick(); // execute for 'ticks' in timer so the queue class instance will know then to initiate execution

Delayed functions with parameters

Do you need to delay the execution of a function that receives a parameter? With ANTIRTOS you can do it easily! Initialize:

 del_fQP<float> F6(8); // // maximum 8 'delayed' functions pointers with parameters in queue

put where you want (here example of 2 functions put into queue):

 F6.push_delayed(your_func_1, 3.14, 1000); // function your_func_1(3.14) will be delayed for 1000 'ticks'
 F6.push_delayed(your_func_2, 3.15, 2000); // function your_func_2(3.15) will be delayed for 2000 'ticks'

in main loop (or other periodic loop) just need to:

void loop() {
.......
F6.pull(); //execute in loop just this super fast function;
}

in some timer or periodic function:

  F6.tick(); // execute for 'ticks' in timer so the queue class instance will know then to initiate execution

Revocation function from conveyers

You may easily revoke your tasks from delayed functional queues like following:

F5.revoke(yourTask); // revoke function (all of the same if there are several of them) from the F5 queue

Kindly find an example of usage revocation on Wokwi!

That's it. Enjoy!

If you are not sure of interrupts priorities, push to different queues in each interrupt

You even may improve your job by dividing all your functions into "weight" groups:

1. Divide all your functions into groups: fast (in one pass), slow-to-complete, and middle functions.
2. Create a separate queue of pointers to these functions for each type.
3. Execute the fastest functions instead of waiting inside of the middle functions.
4. Use the medium and fast pulls for waiting inside of slow procedures.

Try it on Wokwi!