You can install through the Arduino Library Manager. The package name is ESP8266Scheduler.
Include the library in your sketch
#include <Scheduler.h>
#include <Task.h>
#include <LeanTask.h>In your setup function start the scheduler
Scheduler.start(&task);
Scheduler.begin();The scheduler blocks once begun, so the loop function is called by the scheduler BEFORE the first task is runned each time. But it is recommended to avoid using a loop.
Tasks are classes that should inherit the Task class. A task can define a loop() and setup() function
much as the normal Arduino standard.
class BlinkTask : public Task {
protected:
void setup() {
state = HIGH;
pinMode(2, OUTPUT);
digitalWrite(2, state);
}
void loop() {
state = state == HIGH ? LOW : HIGH;
digitalWrite(2, state);
delay(1000);
}
private:
uint8_t state;
} blink_task;IMPORTANT: Tasks must be declared globally on the stack (not a pointer). Failure to do so will crash your device.
Tasks can run yield() and delay() like they normally would. These functions yield control to the scheduler
rather than the ESP8266.
Lean tasks are classes that should inherit the LeanTask class. A lean task can define a loop() and setup() function
much as the normal Arduino standard.
LeanTask doesn't use cont.h (runs in the global context), so yield() works exactly as it would without using the library. This can be useful for saving ram (4k) if the task does not use yield() to interrupt the task. You can use delay() at the end of a task to set the interval.
Good example:
class MemTask : public LeanTask {
public:
void loop() {
Serial.print("Free Heap: ");
Serial.print(ESP.getFreeHeap());
Serial.println(" bytes");
delay(10000);
}
} mem_task;Bad example. The first delay() does nothing:
Source. DO NOT DO THIS!
class PrintTask : public LeanTask {
protected:
void loop() {
Serial.println("Print Loop Start");
delay(5000);
Serial.println("Print Loop End");
delay(5000);
}
} print_task;Tasks can run yield() and delay() like they normally would. The yield() function transfers control to the ESP8266, NOT the scheduler. The delay() function will tell the scheduler that a delay is needed before the next run. If you REALLY need a delay, use ::delay(), but this will block the task and the scheduler.
All examples have the same logic. To optimize RAM, use LeanTask (if possible), because each instance of Task requires 4 kb of RAM.
| File | Description | Free heap (more is better) |
|---|---|---|
| simple.ino | 3 Task | 39896 bytes |
| lean_simple.ino | 1 Task, 2 LeanTask | 48168 bytes |
| subfile_simple.ino | 1 Task, 2 LeanTask + main loop | 48136 bytes |
| TASK_TYPE | Description | Free heap (more is better) |
|---|---|---|
| Task | 12 Task + main loop | 2280 bytes |
| LeanTask | 12 LeanTask + main loop | 51912 bytes |
Method return the status of the task: enabled (true) or disabled (false).
Constructor.
Method return the status of the task: enabled (true) or disabled (false).
The method enable the task.
The method disable the task.
The method sets the task run interval.
The method returns the task run interval.
Adds a task to the multitasking queue.
Starts the scheduler. This function is "blocking". It should be the last call the setup function.
Calls AbstractTask::delay() on the runned task from outside
IMPORTANT: You should not call this method outside for LeanTask tasks. It does not make sense.
Calls AbstractTask::yield() on the runned task from outside
IMPORTANT: You should not call this method outside for LeanTask tasks. It does not make sense.