ColdFire/68K Microcontrollers and ProcessorsのトピックRe: JM and FreeRTOS

JM and FreeRTOS

RajahMC — Sat, 08 Nov 2008 14:35:02 GMT

Does anyone have a FreeRTOS port for the JM128?

Thanks for your time,
Rajah

Re: JM and FreeRTOS

JWW — Tue, 11 Nov 2008 10:11:04 GMT

Rajah MC,

V1 ports do exist... But I'm not aware of the JM128 version yet. I expect it to be easy to do, as I'm aware of another V1 port. The catch is probably finding a good USB stack to use in conjunction with FreeRTOS.

What features do you need supported? Are you using the USB on the JM128?

-JWW

Re: JM and FreeRTOS

RajahMC — Wed, 12 Nov 2008 00:28:20 GMT

Hi JWW,

Thanks for your response. I will need support for USB for the JM.

I did see a FreeRTOS port for QE on the forums.

I am making changes to the QE port to make it work with the JM.
I am stuck with an ILLEGAL_BP when debugging and I have no
clue as to what is causing it. Once I have it working, I was planning
add support for USB.

I was hoping someone had one working already

Rajah

Re: JM and FreeRTOS

JWW — Wed, 12 Nov 2008 12:01:54 GMT

I believe there is a newer version (update for V1) coming out.

I'll double check to see if there are parts (pieces of code) that can be released to improvement stability etc...

-JWW

Note: Latest port on web has ColdFire V2 support

FreeRTOS.org^TM V5.1.0 Now Available:
New ports include ColdFire V2 using CodeWarrior

www.freertos.org

Re: JM and FreeRTOS

RajahMC — Sun, 21 Dec 2008 04:56:45 GMT

Hi JWW,

I managed to take the QE RTOS code base and modified it to work
with the JM demo board. I also added two example tasks.

I am working on adding USB now, getting a good USB stack seems
to the biggest issue right now. Will post code if I get it working.

Thanks for everyones time.

Credits go to thm59 for the QE port.
http://forums.freescale.com/freescale/board/message?board.id=CFCOMM&message.id=4132&query.id=16552#M4132

Rajah

JMMyProgs.zip

Message Edited by t.dowe on 2009-10-21 01:58 AM

Re: JM and FreeRTOS

BSN — Tue, 05 May 2009 21:51:07 GMT

Hi.

I believe there are some errors in this port.

The "dummy save" and "dummy restore" should not be used. Instead, use some "naked" attribute for system ISRs. After the "dummy restore" instructions, registers D0 and D1 might be changed, and just after that task context is saved. That can cause errors in any very simple task.I.e., the context is modified by the system interruption!!!

Also, there is a wrong line that has been (accidentally I suppose) inserted in a system file (queue.c).

Besides in hardware.c functions, inline assembly is used, modifying directly cpu registers without saving their values before. That can lead to errors.

I had also some problem with memcpy from <string.h> in CodeWarrior 6.2 forColdfirev1. That need to be checked out more carefully. But anyway, replacing memcpy in queue.c by a "home made" code in C can fix that problem.

Soon I should be posting a version that works fine for MCF51JM128

Eduardo A.

Re: JM and FreeRTOS

BSN — Tue, 05 May 2009 22:44:07 GMT

As a fast solution for this, just changing the order of things in port.c timer 1 interuption can solve the problem:

Change from this:

interrupt VectorNumber_Vtpm1ch0   vTimerISR( void )
{
    asm( MOVEM.L (A7),D0-D2/A0-A1);            // dummy restore
   asm( LEA 20(A7),A7 );
   asm( UNLK A6);

TPM1C0V += cThisTimerInc;
TPM1C0SC &= (~0x80); /* Reset interrupt request flag */
...

To this:

interrupt VectorNumber_Vtpm1ch0 vTimerISR( void )
{

TPM1C0V += cThisTimerInc;
TPM1C0SC &= (~0x80); /* Reset interrupt request flag */

asm( MOVEM.L (A7),D0-D2/A0-A1);            // dummy restore
   asm( LEA 20(A7),A7 );
   asm( UNLK A6);

...

}

That will do it.

Don't forget to take a look at your memcpy (in queue.c) if you are going to use Codewarrior 6.2 and be careful with those hardware.c functions.

Eduardo

Re: JM and FreeRTOS

wrljet — Mon, 18 May 2009 20:42:29 GMT

Any updates on this project?

Bill

Re: JM and FreeRTOS

BSN — Thu, 21 May 2009 01:48:32 GMT

Hi Bill

I'm sorry for not answering before...(as I had said, that I would..!)

I have searched a little bit about some "naked" attribute, but Aff... it is not that easy to find such a "clear" information! So I was using the fixed version I explained before. (I have also changed that memcpy and the hardware issues...). For memcpy, I could not force the compiler to use my definition of memcpy... it was always taking the codewarrior implementation of memcpy, so I had to change in queue.c "memcpy" by "memcpy_alt". That is clearly not the best way to do it. But it works.. If you know how to force compiler to give preference to user functions instead of his owns, let me know!

In this version, two headers "hardware.h" and "usertasks.h" have been manually inserted into main.c, hardware.c and usertasks.c, because I'm using Codewarior "free", and I'm limited in number of files. I could change those for the includes, but I prefered to let it like that, so I'm sure that what I am posting here works... no mistakes. :smileyhappy:

Eduardo

Port_MCF51JM128.zip

Message Edited by t.dowe on 2009-10-21 01:59 AM

Re: JM and FreeRTOS

wrljet — Thu, 21 May 2009 20:40:11 GMT

Thanks! I will give it a try.

Bill

Re: JM and FreeRTOS

wrljet — Sat, 23 May 2009 00:19:17 GMT

Eduardo,

It's working. Very nice. And I love the way you rearranged the debugger windows.

I didn't know you could do that.

Bill

Re: JM and FreeRTOS

BSN — Sat, 23 May 2009 00:45:21 GMT

You are not serious about the debugger windows....

It's to bad... Now that you said, I should have re-arranged that... :smileysad:

Eduardo

Re: JM and FreeRTOS

wrljet — Sat, 23 May 2009 00:47:43 GMT

I knew you could adjust their relative sizes, but never thought about a layout

like yours. I do like the much larger source code window.

Do you have any gut feeling how much performance overhead the task switches take?

Bill

Re: JM and FreeRTOS

BSN — Sat, 23 May 2009 01:11:00 GMT

I believe it is not that much. I don't know right now to tell you exactely how you can do that with this IDE... But you can measure the context switch time using an oscilloscope and changing port pins values (LEDS...) when context switch occurs.

Eduardo

Re: JM and FreeRTOS

wrljet — Sat, 23 May 2009 01:57:27 GMT

Please excuse my ignorance of this whole topic, but here's an experiment I just ran.

To your existing two userTasks, I added a 3rd task:

void led2Task(void *pvParameters)
{
   (void) pvParameters;

     for( ;; ) {
        LED_4 = !LED_4;
        taskYIELD();
    }
}

Is that a valid experiment?

The LED toggles every 5.2us on the scope, while the other tasks continue to run normally.

Bill

Re: JM and FreeRTOS

BSN — Sat, 23 May 2009 02:04:46 GMT

Yes, of course it is valid - It is a good solution for that measurement. When you yield, the OS will check for tasks that are able to run. Beacause other tasks are all sleeping, that one is the only one able to run, with a priority higher then IDLE task.

So, 5.2 us is the time it takes to switch context

Eduardo

Re: JM and FreeRTOS

wrljet — Sun, 24 May 2009 08:31:55 GMT

Can this RTOS code work with Register calling convention?

Bill

Re: JM and FreeRTOS

BSN — Fri, 29 May 2009 20:05:32 GMT

Hi Bill.

I cannot "guarantee" you that, but I'm pretty sure YES, you can use Register ABI without any problems. That because the context of a task is totally preserved in a context switch. All the pointers (An), all the registers (Dn), SR, the stack,... - everything is preserved.

I don't see any reason why using Reg ABI would not work.

Sorry for not answering before

Best Regards

Eduardo

Re: JM and FreeRTOS

BSN — Fri, 29 May 2009 21:31:18 GMT

Two small corrections for that file:

1 - Change in FreeRTOSConfig.h the processor frequency from 25000000 to 24000000

2 - Change in port.c, in the function TickTimer_SetFreqH:

Set TPM1C0SC = 0x10 instead of TPM1C0SC = 0x1C

Doing so will put ELS bits of TPM1C0SC to zero, and let PTE2 pin free as I/O (that pin is connected to LED1).

Eduardo

Re: JM and FreeRTOS

wrljet — Fri, 29 May 2009 21:48:21 GMT

Eduardo,

Thank you for those corrections.

I had found and changed the 24 MHz myself, and I forgot to mention that to you before.

For what it's worth, I'm soon going to try the FreeRTOS on my own hardware, a few pics

of which are here:

http://www.wrljet.com/junk/Eisbock-unstacked-circled.jpg

http://www.wrljet.com/junk/Eisbock-unstacked-ribbon.jpg

http://www.wrljet.com/junk/Eisbock-stacked.jpg

Bill