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FreeRTOS on The Maple?

(89 posts) (15 voices)

Started 5 years ago by leaflabsandy
Latest reply from nissarup

jadudm
Member

If there was interest, we could work with the Maple community to do a port of occam-pi, a process-oriented, message-passing parallel programming language.

http://concurrency.cc/

The language could be viewed as a "grandparent" to Google's Go. The language is 25+ years old (read: stable, documented, etc.), and we currently support desktop-class hardware as well as the Arduino (with the RCX needing revision and the NXT running, but being refined.)

On the Arduino we run dozens of concurrent processes without too much difficulty, and have recently flown a UAV powered by our tools on the ArduPilot Mega. The Maple would make a nice board, and the team would welcome discussion from the Maple community regarding how we can help support this hardware with additional cool software.

Cheers,
Matt

Posted 5 years ago #
leaflabsandy
Member

Correct me, if I am wrong, but occam-pi runs as a operating system exclusive from the
Maple's Arduinio compatible functions/commands. The just released RTOS MapleCoOS runs
along with the Maple's functions/commands. So to make occam-pi run on the 32 bit
ARM Maple a complete new rewrite is necessary? It is just like porting Python to the Maple. It can be done with some effort and any new RTOS for the Maple would be good IMHO. After all, "The Maple" can also be run in the native mode.

Posted 5 years ago #
x893
Member

Simple example Blink.pde for Maple + FreeRTOS

#include <MapleFreeRTOS.h>

int ledPin = 13; // LED connected to digital pin 13

#define ledSTACK_SIZE configMINIMAL_STACK_SIZE
#define mainFLASH_TASK_PRIORITY ( tskIDLE_PRIORITY + 2 )

static void vLEDFlashTask( void *pvParameters )
{
for(;;)
{
vTaskDelay( 2000 );
digitalWrite( ledPin, HIGH );
vTaskDelay( 200 );
digitalWrite( ledPin, LOW );
}
}

// The setup() method runs once, when the sketch starts
void setup() {
// initialize the digital pin as an output:
pinMode(ledPin, OUTPUT);

xTaskCreate(
vLEDFlashTask,
"LEDx",
ledSTACK_SIZE,
NULL,
mainFLASH_TASK_PRIORITY,
(xTaskHandle *) NULL
);
vTaskStartScheduler();
}

void loop()
{
}

Posted 5 years ago #
leaflabsandy
Member

x893 ... Where is the download link for the Maple FreeRTOS? Your website does not have a link?
Is the systick changes the same between FreeRTOS and MapleCoOS?

Posted 5 years ago #
x893
Member

1. Still in dev stage
2. Yes, the same systick hook as for MapleCoOS

Posted 5 years ago #
leaflabsandy
Member

#3. The use of this library (MapleCoOS) for commercial purposes is still unknown?

Now it has been resolved - Any users could use CoOS freely. (see below from CooCox forum)

Quote: "coco" 1 day ago
Hi rudy,

The conditions that in the "CooCox CoOS's TERMS AND CONDITIONS.pdf" is the old description. The reason that we asked users to declare at market@coocox.com is just to count the number of CoOS's commercial users. Anyhow, we cancel it now. Any users could use CoOS freely. Thanks for your feedback, i'll modify the "CooCox CoOS's TERMS AND CONDITIONS.pdf" file ASAP

Posted 5 years ago #
leaflabsandy
Member

Since x893 is working on the FreeRTOS port to the Maple, there will be two Maple
RTOS(s) now.

The question arises which is better?
It will take some time to compare all the "specific details" of the two but here is
some general differences.

FreeRTOS requires a user to always provide, in the users code, their "FreeRTOS paragraph" They are also pushing users to buy their pdf book so they can easily apply their code. The on-line API is sufficient but for the specific details you need to buy their "expensive" book? FreeRTOS commands are extensive and they indicate all the pros and cons.

CoOS (MapleCoOS) has free docs and manuals. Their RTOS can be used for commercial purposes for free. CoOS commands are limited, compared to FreeRTOS, but they get the job done. Their Free downloaded manual seems rough and needs to be polished.

The specific details of the two RTOSs will be published later...

Posted 5 years ago #
x893
Member

I publish library and sample code here
http://akb77.com/g/mcu/maple-stm32-library-for-freertos/
Also i read info about ChibiOS (http://chibios.sourceforge.net/dokuwiki/doku.php?id=start). Looks not a bad.

Posted 5 years ago #
leaflabsandy
Member

Questions for x893.

In your MapleCoOS RTOS you infer that nothing (should/can) run in the main loop()?
All of the sketch tasks are made to run only in their own priority loops in setup()?

// the loop() method runs over and over again
void loop()
{
}

-------------------------------------------------------------------------

In your MapleFreeRTOS RTOS you infer that you can run other sketch code in the main loop
besides the scheduled sketch code in the setup()?

void loop()
{
// Insert background code here
}

Posted 5 years ago #
gbulmer
Moderator

I know very little about it, but ChibiOS/RT should probably be added too.
http://chibios.sourceforge.net/dokuwiki/doku.php

They say there is an ARM Cortex-M3/GCC version on STM32F10x
http://chibios.sourceforge.net/dokuwiki/doku.php?id=chibios:architectures

and have a 'feature matrix':
http://chibios.sourceforge.net/dokuwiki/doku.php?id=chibios:matrix

Cortex-M3 looks pretty much 'feature complete'.

They post some performance numbers for different processors:
http://chibios.sourceforge.net/dokuwiki/doku.php?id=chibios:metrics

Some more performance comparisons of other RTOS on STM32F are at:
http://yagarto.de/projects/rtoscomp/index.html

The license (for stable versions) is "GPL3 with linking exceptions" (they say it can be used in closed source)
http://chibios.sourceforge.net/dokuwiki/doku.php?id=chibios:license

There is online documentation:
http://chibios.sourceforge.net/dokuwiki/doku.php?id=chibios:documents
but they say they will also sell pdf's, but not yet.

Posted 5 years ago #
x893
Member

MapleCoOS and MapleFreeRTOS not use any codes in loop().
SysTick interrupt used for task switching.
You can use loop() for any codes (as early) but it must presents for compile.
setup() procedure called ones and used for task definitions and task scheduler.
I see ChibiOS but it use other task switching method and currently in porting stage.
As for me CoOS and ChibiOS looks better than FreeRTOS (at my opinion).

Posted 5 years ago #

Maybe Maple-IDE might get a new menu entry for alternative RTOS support?
There could be a few alternative versions of main(), e.g.:

int main() {
    CoInitOS();

    setup();

    CoCreateTask(loop_da_loop, (void *)0, 10,
                 &task_init_Stack[TASK_STK_SIZE-1], TASK_STK_SIZE);

    CoStartOS();

    while(1) { }
}

void loop_da_loop() {
    while (1) {
        loop();
    }
}

So, by default, loop() would be a task :-)

Posted 5 years ago #

x893
Member

Standard main looks as:
int main(void)
{
setup();

while (1) {
loop();
}
return 0;
}
and it's enough for any RTOS functionality and also not need change default arduino codes. More better if anybody add debug menu to arduino toolbar :)

Posted 5 years ago #
gbulmer
Moderator

x893 - I was thinking it might be interesting to provide a very simple API or 'shim' over several of the RTOS functions (so I don't need to choose), so anyone could experiment with more than one RTOS, without having to program to one specific RTOS API.

It would likely only be enough to experiment, but lots of people that do my workshops have real trouble trying to flash LED patterns.
This seems to be a problem that would be straightforward with threads and some form of rendezvous.

My real goal is to help them to learn enough to feel comfortable experimenting with quite complex systems like robots, so making a subset of an RTOS easy to use might be helpful.

Once the setup of the task switching system is removed from setup and loop, then I was hoping it would only need a little bit of work to get a simple system running on two RTOS (to prove it works).

Posted 5 years ago #
x893
Member

gbulmer
i agree. for use task switching you need some primitive functions: define thread, start task engine, semaphores and mutexs, queues. any parallel programming lang. suggest own names and declarations for this. May be some customization with #define or user layer library to hide RTOS level.

Posted 5 years ago #

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