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water pump controllers

 

Iron

 Microchip Pic32 80 Mhz

Iron

Thank you so much

 

Iron

Just getting caught up now as I was not able to log in at normal class time today.  Very interesting stuff. Thank you Jean.

regarding the scheduling algorithm in uC/OS being preemptive...is it strictly priority based? are there considerations for starvation?

 

Iron

@Jean: Yes, I know I have the second edition too, thanks. Personally I regret that I didn't started my own company to develop my own RTOS :).

Iron

bobybacs:
Thanks for the kind words.

The first version of uC/OS was published in 1992.  uC/OS-II in 1998 and uC/OS-III in 2009.

I would invite you to download any of the uC/OS-III books (in PDF format) for free from the Micrium website: www.micrium.com.  The book is somewhere close to 900 pages compared to the 200 or so pages for the 1st book.

Blogger

of course, but back then more than 10 years ago, uC/OS wasn't available for former Mitsubishi (actual  Renesas) so the only solution was to write my own kernel. I must admit that I've used your book  "uC - The Real Time Kernel" and I must say thank you for that.

 

Iron

Doesn't look like there are any other questions.

See you all tomorrow and my accept my appologies for skipping slide #8 and having to come back to it.

Blogger

bobybacs:
The best solution is to write your own RTOS if uC/OS doesn't fit, I have written some years ago my own RTOS for MSP430 family, also for Renesas and for 386EX. Then you can change the scheduling algortithm as you like. It's preaty easy to write a minimalist RTOS for small CPU

Well, writing your own kernel is interesting and could be a fun exercise but, if your company is paying you to develop a product you might consider getting something off-the-shelf.  For example, uC/OS-II and uC/OS-III are quite scalable and can thus fit on small MCUs.  If these two kernel don't satisfy your requirements then you can always find something that will.

Blogger

cghaba:

Is is possible to change the scheduling algorithm in uCOS-II/III?

 

Yes because uC/OS-III is provided in source form and you can easily extract out the scheduling algorithm. 

 

What do you have in mind?  What would you like to replace it with?

Blogger

@cghaba: The best solution is to write your own RTOS if uC/OS doesn't fit, I have written some years ago my own RTOS for MSP430 family, also for Renesas and for 386EX. Then you can change the scheduling algortithm as you like. It's preaty easy to write a minimalist RTOS for small CPU

Iron

bobybacs:

what is the current scheduling algorithm used in uC/OS ?

 

Preemptive scheduling. 

The highest priority task ready to run gets the CPU.

Blogger

cghaba:

Is is possible to change the scheduling algorithm in uCOS-II/III?

 

Yes because uC/OS-III is provided in source form and you can easily extract out the scheduling algorithm. 

 

What do you have in mind?  What would you like to replace it with?

Blogger

smith:

It is better to give a real source code for  a case study.

 

I'm not sure I understand the question.

You can actually download the full source code for both uC/OS-II and uC/OS-III from the Micrium website:  www.micrium.com

 

Again, if used commercially please contact us for licensing.  The source code is provided using the 'honor system'.

Blogger

The vector table is in assembly and default handlers are in assembly.  All others are in C/C+ .

what is the current scheduling algorithm used in uC/OS ?

Iron

There are serveral algorithms in the literature. They could be tested using uCOS-II. 

Iron

cghaba:

Is is possible to change the scheduling algorithm in uCOS-II/III?

 

Yes because uC/OS-III is provided in source form and you can easily extract out the scheduling algorithm. 

 

What do you have in mind?  What would you like to replace it with?

Blogger

cghaba:

Is is possible to change the scheduling algorithm in uCOS-II/III?

 

Yes because uC/OS-III is provided in source form and you can easily extract out the scheduling algorithm. 

 

What do you have in mind?  What would you like to replace it with?

Blogger

Thanks Jean.  I was hoping you had found a silver bullet to the power issues :-)

Enjoyed the presentations -- see you tomorrow and thanks again.

Iron

Lt.Dan

On the subject of statistics, don't some RTOSs provide tools for profiling the system thereby allowing one to fine-tune the system?

 

Yes, for example, we have a cool tool called uC/Probe that displays uC/OS-III statistics at run-time.  In fact, that's just a subset of what uC/Probe can do because it also allows you to display 'any' of your own variables at run-time.  I'll show a screen shot of that on day 5.

 

There are also other 'profiling' tools that shows the tasks on a timeline.  Micrium will be introducing such a product in August.

Blogger

Is is possible to change the scheduling algorithm in uCOS-II/III?

Iron

Lt.Dan

Thanks. Would it be feasible to release any allocated resources upon (or just prior to) deleting a task?

 

Well, if a task delete itself, yes.  If a task is deleting another task, that task might not know that the other task owns resources or, in fcat, that many other tasks will be sharing those resources.  Of course, if you write the whole code base then you might know that you'll also need to delete some of these other tasks.

Blogger

On the subject of statistics, don't some RTOSs provide tools for profiling the system thereby allowing one to fine-tune the system?

Iron

RE: CCarpenter - It would seem that task statistics could be useful in kernel scheduling. Is that something that might be added to future uc/OS kernels?

Iron

CCarpenter:

Thanks.  A different question Jean.  Does the uc/OS-II kernel provide support for the different power-down modes that a given MCU may support?

 

Actually, no.  The reason is that power down modes are very CPU/MCU specific.  Bringing the CPU in low power mode is fairly easy, it's how you bring it back that's a bit harder. 

Blogger

Thanks. Would it be feasible to release any allocated resources upon (or just prior to) deleting a task?

Iron

Lt.Dan

When you say deleting tasks that still have resources, what is meant by a bad situation... locked up waiting for reseources? (is that known as deadlock?)

 

Well, suppose a task is 'waiting for a message' from another task and that other task gets deleted then the waiting task will never get that message.  Of course, if the task waits with a timeout, it will eventually run so, you might be able to take corrective actions.

 

If the task being deleted locked a semaphore (we'll see later this week) then other tasks would not be able to access those resources.

Blogger

if every tasks are in pending state then the idle task could bring the CPU in idle state, is that correct ? Who would wake up the CPU after one of the pending task would be ready to execute ? Maybe it's only a poor design, but in theory it would be possible

Iron

cghaba:

Peripheral initialization should be done in a task or before task are created?

 

Well, it depends on the peripheral.
I typically like to initialize the peripheral that a task manages in the task that manages the peripheral.

For example:

 

MyTask()

{

    Initialize peripheral managed by this task;

    while (1) {

        Your code;

    }

}

Blogger

Thanks Jean!  I look forward to the next sessions.

Iron

Jean, could you please respond to my question too?

Iron

Thanks.  A different question Jean.  Does the uc/OS-II kernel provide support for the different power-down modes that a given MCU may support?

Iron

CCarpenter:
So the task statistics are not used in scheduling by the kernel, is that correct?

That is correct.

Blogger

RyanMac:

Does the kernel typically provide the Idle Task or is that something that the developer has to register with the kernel?

 

Yes, the kernel provides the idle task.  In fact, for uC/OS-II and uC/OS-III, you can 'hook' into the idle task so you can easily add code to bring the CPU in low power mode, if needed.

Blogger

Peripheral initialization should be done in a task or before task are created?

Iron

CCarpenter:

Thanks.  So the task statistics are not used in scheduling by the kernel, is that correct?

 

No, the statistics task is not used for scheduling.

Blogger

smith:

Is  uc/OS-III free ?

 

uC/OS-II is NOT free for commercial use.  In other words, if/when you decide to use uC/OS-II in a commercial product then you must purchase a license allowing you to use uC/OS-II in that product.  Please contact sales@micrium.com for licensing details.

 

However, uC/OS-II is free to use for educational use.

Blogger

Does the kernel typically provide the Idle Task or is that something that the developer has to register with the kernel?

Iron

Thanks.  So the task statistics are not used in scheduling by the kernel, is that correct?

Iron

Hi Jean.  I noticed some fading in and out of audio (about 5 - 10 second intervals) both yesterday and today.  It's as the mike is on a lapel and partially hidden by your collar.  But it's still understandable.

Iron

CCarpenter:

Are you going to discuss how gathering task statistics in the kernel is used Jean?

 

Yes, I will briefly discuss this on day 5.
Basically, you can display how often a task executes by counting the number of context switches to that task (the kernel would do that).  The fact that the counter doesn't increment would indicate that the task is not executing.

Determining the CPU usage on a per task basis could confirm whether your task takes as much time as you'd expect it to or, if not, maybe it's a problem.

Blogger

I find audio quality is impacted by your internet connection.  Check with your IT department if you have problems with the audio.  My audio works better on one PC than on another.

Iron

When you say deleting tasks that still have resources, what is meant by a bad situation... locked up waiting for reseources? (is that known as deadlock?)

Iron

It is better to give a real source code for  a case study.

Iron

4 to 8

all in assembly language

 

Iron

No, the OS is not free - go to http://micrium.com/buy/licensing/ and you can read how our licensing works and watch a little video. Note that the CC button brings up several language translations for those who would like them."

 

Iron

No anything free for uc/OSIII now. But you can download learning free.

Iron

Thanks Jean, see all tomorrow

Iron

Thanks for an excellent presentation.

Ryan:

In an event driven system, can all tasks be in the Pending state?  Or do you always need a background task available for the scheduler to switch to the Running state?

Yes, ALL tasks could be in the pending state.  In fact, when that happens, the CPU runs a special task called the 'idle task' which does nothing or, places the CPU in low power mode.

Blogger

Jennifer, we have had audio problem past one year, each single day because of increasing the participants audio getting worse.

 Appreciate if you can please fix this problem.

Iron

Thanks for the presentation

Please suggest references for formulating the task creation and TCB definition processes

Iron

Is  uc/OS-III free ?

Iron

Audio was perfect today.  Thanks Jean.

Iron

Hi Jean and Jennifer,

This lecture is too short. Half hour may be better. We need more detail informatin.


Thanks.

Iron

Are you going to discuss how gathering task statistics in the kernel is used Jean?

Iron

Thanks. Good lecture. I want to know a little more about the mechisms for context switching and how the kernel might organize the task data (TCBs, etc.) Tomorrow!

I don't recommend deleting tasks for a number of reasons.  One of them is because the task being deleted could own resources that other tasks are expecting.  If those resources are not released then you can end up in a bad situation.

Blogger

@jeniffer & Jean,

Thank you, I see you tomorrow.

Iron

Thanks Jean and Jennifer.

Sugestion: the audio need to be better, mainly to us that don't have english as native language.

Iron

In an event driven system, can all tasks be in the Pending state?  Or do you always need a background task available for the scheduler to switch to the Running state?

Iron

Thank You Jean and Jeniffer

Thanks Jean & Jennifer for another good class! Stay Cool!

Iron

Jean, can you please review again why you don't recommend deleting tasks covered on slid slide 14?

Iron

Thanks Jean and Jennifer

Thanks for the presentation.  It is good to learn about this topic.

Iron

Thanks again!  Good background information.

Iron

Thank you Jean, Jennifer, and Digi-Key

Platinum

Very good presentation

thank you

Thanks again Jean!

Thanks Jennifer!

Iron

Thank you so much Jean and Jenifffer

 

Thanks Jean and Jennifer

Iron

Thank you Jean and Jennifer

Iron

Thanks for the presentation

Iron

Thanks again Jean, Jennifer, & Digi-Key

Iron

Int handled in Assy.

Iron

Hi Jennifer, several of my posts did not show up either.

Iron

Thanks, Jennifer and Jean

Hi Jennifer, some of my type text miss!

Iron

multiple - mostly in C

Iron

Planning for many interrupts, handled in assembly.

Iron

unknown.  Customer developed software.

Iron

8 to 10 ISR in PIC24

Iron

maybr 4 or 5, and C

Iron

I have 5 interrupt sources all implemented in C.

 

Iron

Up to 12 depending upon configuration. always more than 6

Iron

Most designs have 3-5 interrupt sources. All in C.

Iron

4 interrupt sources implemented in assembly.

Iron

5-6 and implementation is in C

Iron

only 1, implemented in C

Iron

12, both assembler and C

Iron

All in 'C', about 5 sources of IRQ

Iron

I have 4 interrupt tasks and mixed assembly and C.

 

Iron

Five interrupt sources in C.

Iron

2 Interrupts and in C

Iron

Typicaly four or five interrupts, handlers implemented in C

Iron

3 sources of interruption. I am using C for ISR

Iron

multiple sources of interrupts, implemented in C

Iron

interrupt service usually in c

Iron

Typically, fewer than 4, never nested

Iron

  Jean's question was:

How many interrupt sources do you have in your current design?

   Are those implemented in C or assembly language?

Audio is fine on safari on my iPad, wifi tethered to my android phone.
Iron

Specific market not yet defined.

Iron

how does OS pick the task which satisfies the wait for event when that task is not high enough in run priority yet?

Small question, Tiva is new Cortex-m4 serial of TI. how about Stalleria? They change product line?

Iron

I too have the same issue with audio...

Iron

@drw36, nostalgic, listening to skip.

Iron

Wirkmanv - I used to have the same problems using IE. Now I use Safari and have no audio problem.

Iron

definetely I agree to drw36...

Iron

Audio today is like listening to a weak shortwave radio broadcast, rising and falling volume. Annoying.

Iron

instrumentation for power plants

Iron

IE, FF, Chrome - All just get about 1 or 2 seconds of audio then it cuts out.  

Iron

aerospace instrumentation and control

Iron

teaching laboartory instrumentation

Iron

Security camera system control.

Iron

Industrial Controls

Iron

consumer and defense

 

Iron

Industrial automation and Medical euipment

Iron

automotive instrumentation

Iron

consumer/enterprise

Iron

Industrial Automation

Iron

Communications industry

Iron

Enterprise audio headsets

Audio Communications

Iron

Mostly consumer grade telecom gear (voice gateways & modem based systems)

Iron

consumer headsets for plantronics

Iron

Tester for Transportation (semi-trailers)

Iron

Current design 64K flash, 4K RAM

Iron

manufacturing/industrial process control and monitoring

Iron

Telecommunications.

Iron

Teaching hardware (teaching microcontrollers)

Iron

commercial / consumer

Iron

Medical equipment interfacing.

 

Iron

Military Instrumentation RADAR.

Iron

Consumer HVAC controls and security / life safety devices.

Iron

medical device industry, vitals signs monitoring, etc

Iron

32bit AVR 256 flash

 

Iron

At least we know this is live, and not recorded.

Iron

Jean is on slide 9

Iron

looks like it is actually slide 9 from what I have

Iron

512k Flash

56k RAM

Iron

On a previous JM128-based project, only 128K FLASH, 16K RAM. Severely resource constrained!

Iron

RAM for one of our projects is 8 GB.  I don't know about ROM

Iron

several MB for current system for both flash & RAM... some sytems I work on have 64KB/8KB flash...

Iron

512K Flash + 128K ram

 

Iron

Multi processors, each with 64K of RAM. ROM minimal.

Iron

Cortax-M4, RAM16K. ROM32M

 

Iron

32k-4M RAM  512k-16M Flash

Iron

8MB RAM and 8 MB Flash

 

Iron

128k Flash, 16k RAM

Iron

  Jean's question was:

How much memory do you have in your current design?

   How much ROM or Flash?

   How much RAM?

Both IE & Firefox - No Audio.  Do not have chrome.  Will look for archived audio tomorrow.  It works.

Iron

Audio levels are rising and falling, as though the speaker is moving away/towards the microphone.

Slide 3: Lines 5 and 6 cannot be swapped?

Iron

have no specific processor in mind

I like to use low speed devices to take advantage of lower power consumption

 

Iron

If you are having trouble with the audio, please try using FF or Chrome. Many people experience issued with IE. Also, please make sure you have the current version of Flash. That makes a big difference.

Intel, ARM, PIC from MHZ to 3.0 GHZ

Iron

Chip under development, speed as fast as possible.

Iron

Good afternoon, everyone

Iron

Audio repeatedly dropping out on me.

Iron

DM8168 - not sure of frequency

Iron

Audio is clear, but disappears again.

Iron

ARM Cortex

 30-50MHz?

Iron

ARM - multiple speeds

 

Iron

AVR 8-bit at 16MHz. And Microchip dsPIC33 at 80 MHz

 

Iron

We're using an ARM core (Am335?) not sure what speed.

Iron

11:03 P.S.T and no sound when I push on the play button except the little commerical piece. Has it started already?

 

Iron

PIC 18 16 MHZ

ARM 120 MHZ

Iron

Hello from Greensboro

Iron

Cortex-M3 with 24 MHz frequency

Iron

ARM SOC based system running around 400 MHz

Iron

processor is likely MSP-430 @ 12MHz

Iron

Audio up We're 1:30 into it.

Platinum

Hi all - The audio is live! If you don't see the audio bar at the top of your screen, refresh your browser. It may take a few refreshes to appear. If you are using IE and are having trouble with the audio, please try FF or Chrome. Some people experience issues with IE. Also, some companies block live streams. If yours does, the class will be available on-demand immediately after the lecture ends.

Hello from Calgary

 

Hello All from Steamy Boston, Audio is loud and Clear Jennifer!

Iron

Hello from Silicon Valley!

 

Iron

can you say when it starts please?

Iron

Hello from hot Toronto.

Iron

Hello from Edmonton, Canada

Iron

Hello from Orlando, FL

Iron

Joining from Santa Cruz, CA

Iron

Hello from Longmont, Colorado

Iron

Up and tasking...

 

Iron

Hello from sunny Seattle! :)

Iron

Greetings from (sunny today) Colorado

Iron

Please join our Digi-Key Continuing Education Center LinkedIn Group at http://linkd.in/yoNGeY

Hi - should have gone home by now in UK

Iron

Be sure to follow @designnews and @DigiKeyCEC on Twitter for the latest class information. We encourage you to tweet about today's class using the hashtag #CEC.

Hi from Mishawaka, IN

Iron

Hello from Montana

Platinum

Good evening from Iasi, Romania

Iron

good day from orage county, CA!

Iron

Greetings from Goiania, Brazil

Iron

Florida online, y'all.

Iron

Hello from Albuquerque.  Wow!  There are two people from Albuquerque here.

Iron

Greetings from Vermont

Iron

Hello from AZ!

Platinum

Huntsville Al onboard

Iron

Austin TX checking in!

Iron

hello from Mishawaka

Iron

Beaverton reporting

Iron

Lunch time, Houston!

Iron

Hello to all from Calgary

Iron

Hello from Beaverton, Oregon

Iron

hello all from Edmonton, Alberta

Iron

Hello from Michigan

Iron

Hot, hotter, hottest

Iron

Please note that some companies block live audio streams. If you don't hear the audio when the class starts, try refreshing your browser. If you still have problems, the class will be archived immediately following the live taping.

Hi everyone, class starts in about 45 minutes. Please prepare by downloading 'Today's Slide Deck' - you should see it above right under 'special educational materials.'

@CurtD, yeppers...lovin' my air conditioning right now.

Iron

Good evening from Valladolid, España (the sunny Spain)

 

Iron

Hello from a very Hot!, Chicago

Iron

Good morning from Chicago.

Iron

hello you guys from SoCal

Iron

Hello from Scottsdale,AZ

Iron

Greetings from Metro Boston, MA. Another steamy 90 degree day! Good to be inside.

Iron

Hello from hot Binghamton, NY

Iron

@vchou: How is the wheather in Greece ? In my vacation I was in Thassos, great place they have very nice beaches and places to visit

Iron

Hello from Timisoara, Romania

Iron

Hi from San Diego, CA

I'm learning to use the FreeRTOS with Atmel SAM4L MCUs. I'm looking forward to this lecture.

Thank you, Jean!

best regards, Spincraft

 

 

Iron

@wirkmanv  Have you checked today?  the audio should be archived along with the slides. 

Iron

Hi from DC!  Looking forward to this; yesterday's lecture was awesome.

Iron

Hello from RA Mayfield Hts. Ohio

Good morning from Panama City, FL.

Iron

Good morning everyone.

Iron

Is there somewhere that I can go to get the complete audio from yesterdays presentation?  I had the slides but only was able to get part of the audio after Jean had actually launched into the Q&A.  It seems that our system buffered the audio and would not release it to me to hear until near the end of the session.  On top of that the first part of the audio was not included.

I tried leaving the session and then rejoining.  The audio would come on for a second or two and then disappear.

Iron

Good morning from Tennessee

Iron

Good morning all.

Iron

Good morning from Portland Oregon

Iron

Good morning from Mobile, AL

It's great to see eager participants! See you here tomorrow at 2 p.m. EST!

First download slide.

Iron

Previewed the slide decks for all 5 days.  Any discussion planned for if/how RT kernel helps prevent and/or how debug tools help debug any problems w/application deadlock/livelock/starvation?

The slides are good. Thank You.

Iron


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