heliosproj / helios Goto Github PK

Sorry, I dind't went through all the code lines, but I have a question regarding coop scheduling.

In:

 if (task->state == TaskStateRunning && task->totalRuntime < leastRuntime) {
        leastRuntime = task->totalRuntime;
        runningTask = task;

you are searching for the task with the least runtime.

In:

  if (runningTask) {
    taskStartTime = NOW();
    (*runningTask->callback)(runningTask->id);
    runningTask->lastRuntime = NOW() - taskStartTime;
    runningTask->totalRuntime += runningTask->lastRuntime;
  }

you write the totalRuntime runningTask->totalRuntime += runningTask->lastRuntime;.

What happens, if the totalRuntime has an overflow?
And all other coop tasks are just before an overflow.
Then this task has the least runtime and will always selected in

      if (task->state == TaskStateRunning && task->totalRuntime < leastRuntime) {
        leastRuntime = task->totalRuntime;
        runningTask = task;
      }

Is that correct? I haven't found a correction in the code for that issue.

Hi, are you planning on supporting Teensyduino / Teensy 4.x boards? What is blocking support, currently?

This architecture is currently unsupported by HeliOS.

Would be nice if we can include it multiple times without breaking stuff :)

In order to do so
#pragma once
should be inserted at top of Helios_Arduino.h :)

I'm trying to compile the notification example given in the documentation but am getting the error: "exit status 1 using typedef-name 'xTaskGetInfoResult' after 'struct'". My code is below but all looks correct, can anyone tell me where I'm going wrong? Compiling for an Arduino Nano with IDE 1.8.15.

#include <HeliOS_Arduino.h>

//Our first task checks the state of the mp3 player
void taskA(int id_) {
  /*
     Obtain the task id of task "B" using its friendly name
     since it should not be assumed that task "B" will always
     have a task id of 2.
     Then check the status of the MP3 player
     pass a 4-byte notification containing the player state to the playAudio task
  */
  xTaskNotify(xTaskGetId("TASKB"), 4, "test");
} //end player state function

/*
   Create the second task "B"
*/
void taskB(int id_) {
  /*
     Obtain the notification bytes and value from the xTaskGetInfoResult
     structure by first making a call to the xTaskGetInfo() function call
     using the task's id stored in id_.
  */
  struct xTaskGetInfoResult* res = xTaskGetInfo(id_);
  /* Because xTaskInfo() can return a null pointer, always check
     that the structure's pointer is not null before accessing
     its members.
  */
  if (res) {
    /*
       res->notificationBytes contains the notification bytes
       res->notificationValue contains the notification value
    */
  }
  /* Always call xMemFree() to free the managed memory allocated by
     xTaskGetInfo();
  */
  xMemFree(res);
}

void setup() {
  /*
     xHeliOSSetup() must be the first function call
     made to initialize HeliOS and its data structures
  */
  xHeliOSSetup();

  /*
     Declare and initialize an int to temporarily hold the
     task id.
  */
  int id = 0;

  /*
     Pass the task friendly name and function to xTaskAdd()
     to add the task to HeliOS. xTaskAdd() will return a
     task id greater than zero if the task is added unsuccessfully.
  */
  id = xTaskAdd("TASKA", &taskA);

  /*
     Pass the task id of the task to set its state from stopped
     to running.
  */
  xTaskSart(id);

  /*
     Pass the task friendly name and function to xTaskAdd()
     to add the task to HeliOS. xTaskAdd() will return a
     task id greater than zero if the task is added unsuccessfully.
  */
  id = xTaskAdd("TASKB", &taskB);

  /*
     Pass the task id of the task to set its state from stopped
     to waiting.
  */
  xTaskWait(id);
}

void loop() {
  /*
     Pass control to the the HeliOS scheduler. xHeliOSLoop() should
     be the only code inside the microcontroller project's
     main loop.
  */
  xHeliOSLoop();
}

Hi guys:
I am trying to make a canbus thermocouple module with HeliOS ; the working flow as follow:
step1: power up and run init scripts for init
step2: create two task 1)get temperature 2)write canbus data and send out
wait for 750ms and make sure MAX6675 get the correct temperature data ,IN the meanwhile canbus data will NOT send out
step3: Task1:get temperature will run every 750ms and write the data in a float struct .And then notify task2 to send data out

I tested example-- WaitNotify.ino ,it work well . so I write my pgm base on WaitNotify.ino,here is source files

sourcefile.zip

The main issue is xTaskNotifyTake(task_) can not attached ,not working

Task1 send out notifications :

void taskThermo_Get(xTask task_, xTaskParm parm_)
{
/* Get the task handle for the task that will receive the
direct-to-task notification. */
xTask WriteCANBUSTask = xTaskGetHandleByName("WRITECANBUS");

    temperature_data.BT_AvgTemp=30.12;
    temperature_data.ET_CurTemp=28.66; 

    Serial.print("task thermo_get");
    Serial.print("  ") ;
    Serial.print(temperature_data.BT_AvgTemp);
    Serial.print("  ") ;
    Serial.print(temperature_data.ET_CurTemp);
    Serial.println(" ");


    if (WriteCANBUSTask){  
        //Serial.println("geted task_writecanbus handler"); 
        /* Send the direct-to-task notification of "HELLO"
        which is five bytes. */
        Serial.println("task WriteCANBUSTask send noti "); --------> it's work 
        xTaskNotifyGive(WriteCANBUSTask,2, "OK");
    }
}

task2 :Receiver notifications
void taskCanbus_Write(xTask task_, xTaskParm parm_)
{
String notif_str = "";
Serial.print("before notif_str");
Serial.println(notif_str);
xTaskNotification notif = xTaskNotifyTake(task_); ------>here ,not working .
notif_str = notif->notificationValue;------>here ,not working .
Serial.print("after notif_str");
Serial.println(notif_str);------->print out nothing...which is suppose is 'OK'

if ( notif ){. -------> here is not working neither
notif_str = notif->notificationValue;-------> here is not working neither
Serial.println(notif_str);-------> here is not working neither
xMemFree(notif);-------> here is not working neither
}

The rest of codes is the same as example ino file but the task name....
create task as below:
xTask GetThermoTask = xTaskCreate("GET_THERMO", taskThermo_Get,NULL);
xTask WriteCANBUSTask = xTaskCreate("WRITECANBUS", taskCanbus_Write, NULL);

and then set task in waiting mode :
xTaskWait(GetThermoTask);
xTaskWait(WriteCANBUSTask);
and set sending notify task in running mode which loop in 1s.
xTaskChangePeriod(GetThermoTask, 1000); //1000ms

Thank you for you guys answering!!!
Best wishes!!!

Hi!
I had a question: is it possible to pass parameters to a task you're creating?
So for example have two buttons but with a single task definition?
void taskButton(xTaskId id_, const uint8_t port)
which then is called with something like:
int p = 1; id = xTaskAdd("TASKSW1", &taskSW, p)

Hi guys:
I am learning how to use Queue of HeliOS , my code is not working ,I am not sure my codes is correct.Please do me a favor to explain how to use the function Queue in HeliOS .Thanks
here is my code :
main.cpp.zip

I create tasks, task1 and task2 are just sending message to queue ,and taskprint will read the message
and print it out . It's very simple .
Question 1 :So should I suppose to create a xQueue Queue1 = xQueueCreate(8) ？
Question2: How can I get the handler of Queue in Task?

void Task1(xTask task_, xTaskParm parm_) {
char userID="1";
xQueue Queue1; -------> for Queue1 handler Am I correct ? if I omit this line ,compiler will error : Queue1 is not declared.
if (xQueueIsQueueFull(Queue1) == false ){
xQueueSend(Queue1,
1,
"1" );
Serial.println("TASK1 sended");
} else {
Serial.println("QueueMsg is full");
}
}

Thanks you again!!!!
Best wishes!!!

I'm trying to compile a HeliOS program for Arduino Nano RP2040 Connect (RP2040 processor from Raspberry Pi Pico), it says:

"This architecture is currently unsupported by HeliOS. If building for Linux or Microsoft Windows, make sure to un-comment OTHER_ARCH_LINUX or OTHER_ARCH_WINDOWS in HeliOS.h."
#error "This architecture is currently unsupported by HeliOS. If building for Linux or Microsoft Windows, make sure to un-comment OTHER_ARCH_LINUX or OTHER_ARCH_WINDOWS in HeliOS.h."

Could you please add support for this architecture?
Thanks!

Hi guys:
i am trying to compile the following code in vscode+platfromIO :
code.zip
Not success, here is the output

PLATFORM: Espressif 8266 (4.1.0) > WeMos D1 R2 and mini
HARDWARE: ESP8266 80MHz, 80KB RAM, 4MB Flash
PACKAGES:

• framework-arduinoespressif8266 @ 3.30101.0 (3.1.1)
• tool-esptool @ 1.413.0 (4.13)
• tool-esptoolpy @ 1.30000.201119 (3.0.0)
• toolchain-xtensa @ 2.100300.220621 (10.3.0)
  LDF: Library Dependency Finder -> https://bit.ly/configure-pio-ldf
  LDF Modes: Finder ~ chain, Compatibility ~ soft
  Found 41 compatible libraries
  Scanning dependencies...
  Dependency Graph
  |-- MAX6675 library @ 1.1.0
  |-- HeliOS @ 0.3.5
  |-- SPI @ 1.0
  |-- autowp-mcp2515 @ 1.0.3
  | |-- SPI @ 1.0
  Building in release mode
  Compiling .pio/build/LGT8F328P_esp8266/src/main.cpp.o
  Generating LD script .pio/build/LGT8F328P_esp8266/ld/local.eagle.app.v6.common.ld
  Compiling .pio/build/LGT8F328P_esp8266/lib4af/MAX6675 library/max6675.cpp.o
  Compiling .pio/build/LGT8F328P_esp8266/lib3ef/HeliOS/device.c.o
  Compiling .pio/build/LGT8F328P_esp8266/lib3ef/HeliOS/mem.c.o
  Compiling .pio/build/LGT8F328P_esp8266/lib3ef/HeliOS/port.c.o
  Compiling .pio/build/LGT8F328P_esp8266/lib3ef/HeliOS/queue.c.o
  Compiling .pio/build/LGT8F328P_esp8266/lib3ef/HeliOS/stream.c.o
  Compiling .pio/build/LGT8F328P_esp8266/lib3ef/HeliOS/sys.c.o
  Compiling .pio/build/LGT8F328P_esp8266/lib3ef/HeliOS/task.c.o
  Compiling .pio/build/LGT8F328P_esp8266/lib3ef/HeliOS/timer.c.o
  Compiling .pio/build/LGT8F328P_esp8266/libe14/SPI/SPI.cpp.o
  Archiving .pio/build/LGT8F328P_esp8266/lib3ef/libHeliOS.a
  Indexing .pio/build/LGT8F328P_esp8266/lib3ef/libHeliOS.a
  Compiling .pio/build/LGT8F328P_esp8266/lib187/arduino-mcp2515-master/mcp2515.cpp.o
  src/main.cpp: In function 'void setup()':
  src/main.cpp:146:37: error: invalid conversion from 'const char' to 'const xChar' {aka 'const unsigned char*'} [-fpermissive]
  146 | xTask GetThermoTask = xTaskCreate("THERMO",taskThermo_Get,&BT_ArrayIndex);**
  | ^~~~~~~~
  | |
  | const char*
  In file included from src/main.cpp:4:
  lib/HeliOS/src/HeliOS.h:1194:32: note: initializing argument 1 of 'Task_t* xTaskCreate(const xChar*, void (*)(xTask, xTaskParm), xTaskParm)'
  1194 | xTask xTaskCreate(const xChar *name_, void (*callback_)(xTask task_, xTaskParm parm_), xTaskParm taskParameter_);
  | ~~~~~~~~~~~~~^~~~~
  The same code in LGT8F328P is OK and working well ...
  Please have a check !
  Thank you very much!

Hi!
I loaded the example code in the arduino ide for blink and it didn't do anything.
I then loaded the basic example code for blink and it worked without problems.
I didn't change anything in the example - should i have?
I am using an arduino nano and i know HeliOS is about the limit for it, might that be a problem?
I have no experience with OS on microcontrollers and previously did everything "by hand".

I think that could be a problem:

If you have for example 15 timer tasks.

Ten of them runs every 10ms for example and five of them runs every 200ms. That five are at the end of the task list.
It could be that this five tasks will never run, because the scheduler always make a TaskListRewind(), start from the front of the list and limit the waitingTask[waiting] to 8.
Because of that limit and the reset of the list it could be, that the scheduler will never reach the 200ms tasks because the 10ms task want alway to run.

Hi Guys :
I am learning how to make a multi-tasks project with HeliOS 0.3.3 ,I make the code as following:

heliOS_learning.zip
which is base on HeliOS example "Coop" .I am trying to run 3 tasks in this program
1:blink the LED (base on example "Blink")
2: two task-nobody (just delay(XXX) and print a letter out to serial port

Here is the task function:

void taskShort_main(xTask task_, xTaskParm parm_) {
int ledState = DEREF_TASKPARM(int, parm_);
Serial.print("led 1 ");Serial.println(ledState);
if (ledState) {
digitalWrite(LED_BUILTIN, HIGH);

Serial.print("led 2 ");Serial.println(ledState);

ledState = 0;

Serial.print("led 3 ");Serial.println(ledState);

} else {
digitalWrite(LED_BUILTIN, LOW);

ledState = 1;

Serial.print("led 4 ");Serial.println(ledState);

}
DEREF_TASKPARM(int, parm_) = ledState;
Serial.print("led 5 ");Serial.println(ledState);
return;
}

And serial print out :

08:38:03.355 -> L
08:38:03.966 -> M
08:38:03.966 -> led 1 0 timeloop1 in-value =0 ,init value ,OK
08:38:03.966 -> led 4 1 timeloop1 change ledstate ,working good
08:38:03.966 -> led 5 1
08:38:04.342 -> L
08:38:04.953 -> M
08:38:05.375 -> L
08:38:05.375 -> led 1 0 timeloop2 in-value =0?,suppose to be 1 ,working not OK now
08:38:05.375 -> led 4 1 timeloop2
08:38:05.375 -> led 5 1

The var Ledstate do changed in Task "taskShort_main" and pass-thought out to DEREF_TASKPARM(int, parm_) (LED 1 in-value = 0 , LED4 out-value = 1 ),but in the next task Schedule Led1 read in value still is 0 ,suppose to be LED1 = 1 .

so , I make the same coding in example "Blink" , as following :

Blink-check.zip

And serial print out :

08:46:44.589 -> led 1 0 timeloop1 in-value =0 ,init value ,OK
08:46:44.589 -> led 4 1 timeloop1 change ledstate ,working good
08:46:45.625 -> led 1 1 timeloop2 in-value =1 ,from lastloop led4 out-value ,working good
08:46:45.625 -> led 2 1 timeloop2
08:46:45.625 -> led 3 0 timeloop2 change ledstata, output value .
08:46:46.602 -> led 1 0
08:46:46.602 -> led 4 1
08:46:47.653 -> led 1 1
08:46:47.653 -> led 2 1
08:46:47.653 -> led 3 0

the coding is work....

I have tried Arduino Nano , LGT8F328P Nano , both "blink" program running OK , "Coop+Blink" not OK ,
I also tried D1 mini ,but seems HeliOS 0.3.3 not working good . I can not locate where is "ARDUINO_ARCH_ESP8266" in HeliOS.h.

I am not sure which parts is not OK now ......
Would you Please help me to check it out !!!!
Thanks all guys and best wishes !!!

The time value in HeliOS is defined as unsigned long, which most likely will be 32 Bit on typical embedded platforms.

With a time resolution of one microsecond it will "wrap around" (start over from zero...) after ~4295 seconds which is not much longer than one hour. To have a practical use of HeliOS the effects of timer overflow have to be mitigated. Not sure if this is handled in the code , I quick review shows this line in HeliOS.c:

 if (NOW() - waitingTask[i]->timerStartTime > waitingTask[i]->timerInterval) 

This will at least work also in overflow case, because all values are unsigned. But I'm not sure if all other cases handle wrap around well. At least users should be warned in the documentation that it will happen quite frequently.
Another possibility would be to ensure that the time values are 64 Bits, but this may be very expensive on 8 Bit AVRs (not even sure if avr-gcc supports 64 Bit integers...).
A general question is if relying on standard C "unsigned long" is an issue with portability, because "long" can be theoretically anything. Most portable software systems either define either their own integer types (like "u32", "u64") or include stdint.h
At least you should define a type for such a very critical value like time (e.g. "t_helios_time") with the possibility to adapt it for different ports.
This would also allow e.g. to run HeliOS in x86_64 Linux userland (where long is 64 Bits) but still emulate the behavior of a 32 Bit MCU platform.

Default size of the OS's heap block (array static Byte_t heap[HEAP_RAW_SIZE] in mem.c) is IMHO a way too big for most usage scenarios. With the default values of CONFIG_HEAP_SIZE_IN_BLOCKS = 512 and CONFIG_HEAP_BLOCK_SIZE = 32 it takes 16 kB of RAM memory which is ridiculous number for most popular AVR-based Arduino boards like Uno, Mini, Micro, Leonardo with around 2 kB of SRAM. Even Arduino Mega has only 8 kB. For the ESP8266 boards, like Wemos D1 and clones, it eats half of RAM.

My proposal is to move these configs into defines.h section with architecture specific options. Then for example ARDUINO_ARCH_AVR should set defaults to no more than 128 B, current value of 16 kB may be usable only on architectures like ARDUINO_ARCH_SAM, ARDUINO_ARCH_SAMD, ESP32 ond other bigger ones with RAM counted in hundreds of kB or more.

🎯 Help us help you by filling out this issue completely. This issue is ONLY for bug reports. If you are seeking support, please submit a support request.

1. Describe, in detail, the bug you have encountered and how to reproduce it (if providing a source code excerpt, use a markdown code block and please do not provide screenshots of source code):

HeliOS source files conflict with Arduino files under Windows because filenames are the same. Under Linux they are not the same (capital S versus lowercase s). This leads to a lot of errors in compiling under Windows.

2. What results, output, behavior are you expecting?

Same result in Windows as in Linux.

3. What version of HeliOS are you using?

The latest 0.4.1.

4. Provide the following details about your development environment and development board/microcontroller:

OS [Windows, macOS, Linux]: Windows

OS Version [Windows 10, Ventura, Ubuntu 22.04]: 7 and 10

IDE [Arduino IDE, PlatformIO, STM32CubeIDE, Keil]: Platform IO

IDE Version: 1.70.3 and the latest (18.x)

Board/MCU Mfg [Arduino, PJRC, ST Micro]: Arduino MEGA 2560 pro

Board/MCU Model [UNO, Teensy 4.1, NUCLEO-F429ZI]:

5. Are you experiencing any compiler or linker errors? If so, copy and paste them here (please do not provide screenshots):

Many. Please, take a look at following link for more details and a solution:
https://community.platformio.org/t/strange-issue-with-compiling-under-linux-fine-fails-badly-in-windows/38572/2

7. Attach a copy of your source code file(s) so we may compile them if needed:

Hi:
Here is my case:
I am trying to make a canbus thermocouple module with HeliOS ; the working flow as follow:
step1: power up and run init scripts for init
step2: create two task 1)get temperature 2)write canbus data and send out
wait for 750ms and make sure MAX6675 get the correct temperature data ,IN the meanwhile canbus data will NOT send out
step3: Task1:get temperature will run every 750ms and write the data in a float struct , notify task2 send out data
Task2:canbus data will send out data .

After I read thought examples pgm :Blink.ino and coop.ino .I don't quiet to understand the difference between xTaskResume() and xTaskWait()
In Blink.ino ,after create and check the task is OK .
xTaskWait(blink); -------->Is that means task in suspended mode ,not running
xTaskChangePeriod(blink, 1000); ------>that means wait for 1s , as a timer ,like function delay() of arduino ?

 In coop.ino,after create and check the task is OK . 
   xTaskResume(shortTask); -------->Is that means task run immediately？

For further study,How to use MUTEX (in freeRTOS ) to lock the data?

Thank you for you guys answering!!!
Best wishes!!!

Hi!
First of all, congratulations for your nice project HeliOS. I liked your project and I'd like to contribute it for porting HeliOS to PIC18 devices of Microchip and maybe for STM microcontrollers in the future. My contributions would be in bare metal code form to interface your OS with the low level built-in hardware like timers, UARTs etc. I have looked through the guides but haven't seen any contributing guide. Can you provide a porting guide where you describe the systems interfaces briefly unless you have one, then please provide the link here so I can make use of it.
A brief guide would be very time saving, you know, we are kind of busy and time limited because of the full time work hours.

Encountered a strange problem which I cannot find a solution. Linking problem with multiple files that link fine when using FreeRTOS but not with HeliOS.

Made a simple test to verify this issue as well.

What works:

• single file where the whole code is
• includes arduino.h and helios.h and few other includes.
• compiling, linking, download and code runs properly

What does not work:

• a dedicated local.h with prevention to include multiple times (#ifndef...) which contain arduino.h and helios.h
• 2 source files, where the same code as in the working example is located in one file and in the 2nd file there's only one dummy task that does nothing + include of local.h
• one additional include file (dummy.h) which includes local.h and declaration of the dummy task (extern) so that it can be found
• main code is modified to include local.h and registration of dummy-task
• compile fine, link fails

.pio/build/megaatmega2560/src/main.cpp.o (symbol from plugin): In function display':
(.text+0x0): multiple definition of xByte2String(unsigned int, unsigned char*)' .pio/build/megaatmega2560/src/dummy.cpp.o (symbol from plugin):(.text+0x0): first defined here collect2: error: ld returned 1 exit status *** [.pio/build/megaatmega2560/firmware.elf] Error 1

I have been using this local.h approach for a long time successfully e.g. with FreeRTOS but for some reason HeliOS doesn't like this at all (or linker doesn't like with HeliOS).

local.h:
`#ifndef local_h
#define local_h

#include <Arduino.h>
#include <HeliOS.h>

#endif
`

dummy.h:
`#include "local.h"

extern void TaskDummy(xTask task_, xTaskParm parm_);`

dummy.c:
`#include "local.h"

void TaskDummy(xTask task_, xTaskParm parm_)
{
// nothing
}`

main.c (beginning of the file):
#include "local.h" #include <SPI.h> #include <Adafruit_GFX.h> #include <Arduino_ST7789_Fast.h> #include "dummy.h"
There comes usual setup() and loop() functions. In setup tasks are registered etc.

2. What results, output, behavior are you expecting?

Expectation is that the code would link normally with HeliOS.

3. What version of HeliOS are you using?

heliosproj/HeliOS@^0.4.1

4. Provide the following details about your development environment and development board/microcontroller:

OS [Windows, macOS, Linux]: Linux

OS Version [Windows 10, Ventura, Ubuntu 22.04]: OpenSUSE Tumbleweed

IDE [Arduino IDE, PlatformIO, STM32CubeIDE, Keil]: PlatformIO

IDE Version: 1.85.2

Board/MCU Mfg [Arduino, PJRC, ST Micro]: Arduino MEGA 2560 Pro

5. Are you experiencing any compiler or linker errors? If so, copy and paste them here (please do not provide screenshots):

.pio/build/megaatmega2560/src/main.cpp.o (symbol from plugin): In function display':
(.text+0x0): multiple definition of xByte2String(unsigned int, unsigned char*)' .pio/build/megaatmega2560/src/dummy.cpp.o (symbol from plugin):(.text+0x0): first defined here collect2: error: ld returned 1 exit status *** [.pio/build/megaatmega2560/firmware.elf] Error 1

7. Attach a copy of your source code file(s) so we may compile them if needed:

HeliOS_test.zip

Hi all!

I'm trying this RTOS to write the software for a digital guitar effect pedal but I ran across some issues (other than the docs not being up-to-date) with regards to a dynamically timed task...

First, I have a timed task that runs every 10ms which reads a pot value (between 0 and 1023) and calculates a delay tempo from it. This sets the timer of the next task accordingly.

long delay_time_us = long(map(delay_time, 0, 1023, 53, 626)) * 1000;
xTaskSetTimer(xTaskGetId("TASKTEMPO"), delay_time_us);

This "TASKTEMPO" is a very simple task that toggles a LED:

void taskTempo(xTaskId id_) {
  if (smode == SMODE_TEMPO)
    analogWrite(pin_rgb_g, 127 * tempo_blink);

  tempo_blink = !tempo_blink;
}

If I only have those two tasks, it works fine. However, when I add a couple more tasks, things start to get a little different. The timing seems still alright but often the task completely skips... Meaning that the LED blinks irregularly... Based on the concept of cooperative scheduling I would assume that the priority is high (as the taskTempo is very short) but it doesn't seem to be the case... Can I somehow assign priorities to tasks or is there a different solution to the issue?

Hi!
First of all, congratulations for your nice project HeliOS. I liked your project and I'd like to contribute it for porting HeliOS to PIC18 devices of Microchip and maybe for STM microcontrollers in the future. My contributions would be in bare metal code form to interface your OS with the low level built-in hardware like timers, UARTs etc. I have looked through the guides but haven't seen any contributing guide. Can you provide a porting guide where you describe the systems interfaces briefly unless you have one, then please provide the link here so I can make use of it.
A brief guide would be very time saving, you know, we are kind of busy and time limited because of the full time work hours.

ID require you to search through the list to find corresponding task. I propose to replace ID with pointer to Task struct which will remove unnecessary lookup.

If you want to prevent user from messing with internals, I also propose to declare structs in separate header and typedef them as void in public header. This way from user point it's only a void pointer and he cannot change internal stuff whereas HeliOS functions will be able to do so.

I get follwowing result on UNO:

ACBACBACBL
ACBACBACBL
ACBACBACBL
ACBACBACBL
ACBACBACBL
ACBACBACBL
ACBACBACBL
ACBACBACBL

while using following code:

`/*

• HeliOS Embedded Operating System
• Copyright (C) 2020 Manny Peterson [email protected]
• This program is free software: you can redistribute it and/or modify
• it under the terms of the GNU General Public License as published by
• the Free Software Foundation, either version 3 of the License, or
• (at your option) any later version.
• This program is distributed in the hope that it will be useful,
• but WITHOUT ANY WARRANTY; without even the implied warranty of
• MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
• GNU General Public License for more details.
• You should have received a copy of the GNU General Public License
• along with this program. If not, see https://www.gnu.org/licenses/.
  */

/*

• Additional documentation on HeliOS and its Application
• Programming Interface (API) is available in the
• HeliOS Programmer's Guide which can be found here:
• https://github.com/MannyPeterson/HeliOS/blob/master/extras/HeliOS_Programmers_Guide.md
  */

/*

• Include the standard HeliOS header for Arduino sketches. This header
• includes the required HeliOS header files automatically.
  */
  #include "HeliOS_Arduino.h"

/*

• The task definition for taskShort() which
• will perform 100,000 arbitrary floating point
• operations.
  */
  void taskShortA(int id_) {
  float a = 0.0f;

for (int32_t i = 0; i < 1000; i++)
a *= 3.14f;

Serial.print("A");
}

void taskShortB(int32_t id_) {
float a = 0.0f;

for (int32_t i = 0; i < 10000; i++)
a *= 3.14f;

Serial.print("B");
}

void taskShortC(int32_t id_) {
float a = 0.0f;

for (int32_t i = 0; i < 40000; i++)
a *= 3.14f;

Serial.print("C");
}

/*

• The task definition for taskLong() which
• will perform 1,000,000 arbitrary floating point
• operations.
  */
  void taskLong(int32_t id_) {
  float a = 0.0f;

for (int32_t i = 0; i < 40000; i++)
a *= 3.14f;

Serial.println("L");
}

void setup() {
/*

• Declare and initialize an int to hold the
• task id.
  */
  int id = 0;

Serial.begin(9600);

/*

• Call xHeliOSSetup() to initialize HeliOS and
• its data structures. xHeliOSSetup() must be
• called before any other HeliOS function call.
  */
  xHeliOSSetup();

/*

• Add the task taskShort() to HeliOS by passing
• xTaskAdd() the friendly name of the task as well
• as a callback pointer to the task function.
  */
  id = xTaskAdd("TASKSHORTA", &taskShortA);

/*

• Call xTaskStart() to start taskShort() by passing

• xTaskStart() the id of the task to start.
  */
  xTaskStart(id);

  id = xTaskAdd("TASKSHORTB", &taskShortB);
  xTaskStart(id);

  id = xTaskAdd("TASKSHORTA", &taskShortC);
  xTaskStart(id);

/*

• Add the task taskShort() to HeliOS by passing
• xTaskAdd() the friendly name of the task as well
• as a callback pointer to the task function.
  */
  id = xTaskAdd("TASKLONG", &taskLong);

/*

• Call xTaskStart() to start taskLong() by passing
• xTaskStart() the id of the task to start.
  */
  xTaskStart(id);

Serial.println("START");

}

void loop() {
/*

• Momentarily pass control to HeliOS by calling the
• xHeliOSLoop() function call. xHeliOSLoop() should be
• the only code inside of the sketch's loop() function.
  */
  xHeliOSLoop();
  }`