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good presentation, time flies.  Would like to go through some other functions mentioned e.g. debugger, and various control bit functions.  Easy enough to read up on ... may have to try to get a DEV kit

power saving modes are important in most new designs I use

No experience with lock up yet

No experiments with INT at PWR

Have not used the power save feature on this device, but have on others.

Power management can be important but I think these features are available on some other processors, but these features could come in handy, have worked on a few projects were the equipment is shutdown for extended periods of time.  This product could save some power and external devices... maybe.

Iron

@Chuck - no, have not measured the actual core power savings on a cortex

Iron

@Chuck - yes, have used the power saving mode

Iron

Great to have access to the recorded sessions.

Iron

Missed the live lecture due to travel...

Iron

Thanks another useful lecture

Hi picking up the last few presentations a bit late

Thanks Paul; great presentation

Iron

chuck,

Sorry I missed today's presentation.  Here  are my answers to the questions de jour:

!. I have not used Power Save features of cortex but I have on other processors.

2.I do plan to gather empirical data for power consumption on an upcoming solar project.

I have never used or experienced hard fault or locup.  It seems though, that you would want to use an NMI to come out of it so as to preserve the environment where the crash of the crash handler occured.  Olease clarify as the slide said either NMI or RESET would revive it?

Iron

Once the Cortex-M0 goes into a lock-up condition; the only way to bring the system back is through a rest. 

 

Is this a manual reset, requiring human intervention?  Obviously the WDT may no longer be operating so a self reset won't happen.  (is this correct?)

 

 

And what about power cycling?  When might a reset (using a reset button in my product) not be enough to recover the system and under what conditions might it be necessry to actually recycle power?

Iron

no powersaving techniuqes used yet...

Iron

Good information, but I am not seeing a whole lot here that is not available on just about every modern microcontroller, 16-bit and even some 8-bit processors.

Iron

On bit banding: some processors provide bit-twiddling instructions to set, clear, toggle, and/or test a single bit in an atomic manner. I cannot see that bitbanding buys anything beyond this, and it consumes 8x or 16x address space over and above the actual bit masks being manipulated. What's the upside?

Iron

thanks, good presentation

Iron

@phildani7, that's how I understand it.

Iron

oh okay! that explains!! so it is nothing but a bit addressable location!?

Iron

thanks paul and all, see you tomorrow.

Iron

I've had to "fiddle" witht bits in a register by...

read the byte, and/or the value, write it back

just to set or clear a bit.

 

memory mapping the bit to an address sounds a lot easier

Iron

thanks Paul, see you tomorrow

Iron

okay, thank you bobybacs and Paul

Iron

So, time to sign off.  Thanks for your

time and attention.  See you tomorrow!!

Paul.

Blogger

bit-banding is the same as PICs bit-addressable bytes ?

Iron

maybe because iam an assembly person and not C person!

Iron

@bobybacs: me neither, but I will look at

it on one of our M3's - doubt I'll get to it

by tomorrow though.  Thanks for the question/answer.

Blogger

@bobybacs: thank you. I am still not able to appreciate it. Anyhow let me read through docs.

Iron

@bobybacs, quick draw!

Iron

@danlafleur: I just wanted to post the same link :)

Iron

Bobybacs: good on bit banding, have you used it?

Blogger

Yeah - we will touch on Nuvoton tomorrow.  I will

try to address cost of these parts more, it's difficult

cause cost is a function of device features AND the

package the device is purchased in.

Blogger

@phildani7:

Bit-banding maps a complete word of memory onto a single bit in the bit-band region. For example, writing to one of the alias words will set or clear the corresponding bit in the bitband region.

This allows every individual bit in the bit-banding region to be directly accessible from a word-aligned address using a single LDR instruction. It also allows individual bits to be toggled from C without performing a read-modify-write sequence of instructions

Iron

@przemek  The part was Numvoton MINI51ZAN.  Only 4K Flash. Mis-typed the price, it is actually $.708.  They might have one less expensive that my simple search did not find. I was only interested in ball park. I don't do really large runner designs any more in my current position. I am very impressed with the Cortex price/performance even in small quantities - one reason I am attending this course.  - Thanks Paul for presenting it!

Iron

Paul thanks again - looking forward to tomorrow.

 

Bit Banding... a cool topic, but M0 does not have it.

I therefore won't have time to get into it this time around...sorry.

Blogger

Oh yes, I was speaking about cost-reduction

of a 4-bit smoke detector system.  This was running

at 1M pieces a year, we at Orchid identified a basket

of electronics cost reductions that saved approx $1.34,

part of this was switch from one four-bit micro to another.

Now that was squeezing for every penny....

Blogger

what is bit banding? will you touch on that tomorrow?

Iron

Pricing questions:  Yes, Actual pricing is

highly package dependant.  The is the

silicon cost and there is the cost of the package.

If you actually do have need to negotiate super

low, high volume (1M plus) pricing, you will find

that counter-intuitively certain packages are much

less expensive than others.

Blogger

Yes, I know you negotiate with the factory when you get up to those kind of quanties (used to work for a contract manufacturer). So you think you could get that price now?

Iron

You mentioned cost reduction in one of your early examples today. This usually requires code migration from one processor to another. I realize this is a substantial topic, but could you speak to this briefly and how best to minimize this effort if one were to stay within the ARM family?

Iron

C-programming, lots of good books, I like

Kernihan and Richie, but what do I know, I'm

a purist....

Blogger

@garysxt--is the $0.78 part a 11xx?

Gold

any good book to start with C programming on ARM Cortex?

Iron

No no, you get 'special' pricing by negotiating special

contracts.  Standard pricing - you know like dealer-delivery

MSRP pricing, is all that is published.

Blogger

There was an early comment about $.25 Cortex M0 some day. Did a quick search on Digi-Key. Least expensive one was $.78 in 10K Qty. Paul mentioned $.25 in million pieces. Probably not at that price yet, but I would not bet against it happening in a couple of years.

Iron

Yes, you can hear this and all previous lectures, including from other tracks.

Iron

@TDMengineer - Yes - just wait until after the live chat is done and then to the archive.

Yes its archived, probably right away...

Blogger

Is it possible to listen to today's audio again?

RTC is not part of the core.  RTC is device

vendor specific!!  The only 'timer' that the core

has is SYSTICK.

Blogger

Wikipedia has helpful info on the THUMB instruction subset for ARM - try http://en.wikipedia.org/wiki/ARM_architecture#Thumb

Iron

I know of no ARM device implementations that

actually run at 0.8V.  That's low!!


Best today I think is 1.8V.

Blogger

Thank u for clarification

 

Iron

@jsp, it would be nice to have a benchmark test that incorporated the use of sleep modes between fast execution sessions to put a quantifiable metric on that "lower average power". Anyone know of one?

Platinum

WIC - Sorry if I was unclear about this.  WIC is not an instruction.

It stands for the Wake-up Interrupt Controller, it is a peripheral

that some vendor use as another way to wake-up their devices.

Its also an M0+ core peripheral.  I will clarify this tomorrow, thank

you for asking!!

Blogger

Q: Is the RTC part of the core or the device vendors append them?

Iron

Device vendors have incorporated Watch Dog timers

into their implementation of parts to sell, the CORTEX-M0

core is independant of that, thus there is no CORE peripheral

that is Watchdog.  Is that clear - or should I try to word it better?

 

Blogger

@przemek - I find most ARMs will actually run overall lower power than 8, 16 bitters (faster exec when awake).

Iron

Sorry---I meant "few remaining advantages of 8-bitters is low VOLTAGE operation"

Gold

Cortex M0 instructions are all 16 bit THUMB style,

I wish I had time to get more into this....

Blogger

Thank you Paul, Chuck

Iron

Q: how does the processor receive WIC instruction when it is already in deep sleep mode?

Iron

Agreed with SE - Presenters and presentations like this are extremely valuable and should be encouraged for future weeks.

RE: watchdog, ext watchdog can be logged externally to indicate a failure.  sometimes want that

 

Iron

Q. What are the differance if any between described instruction set and " Thumb instruction set " for cortex M0/M3 ?

One of the few remaining advantages of 8-bitters is low power operation. There are various 8051, PIC and MSP430 variants that operate down to 0.8V. Are there ARM cores that match that?

 

Gold

Great information, I look foward to future broadcasts.

 

Wayne

Iron

The clock speed can be dynamically changed, that is changed

by the running application - one must remember that other

peripherals outside the core could be affected.

Blogger

Thanks Paul and Chuck.

Iron

Thanks to both - excellent series

Iron

Thank You Paul. That was great and thanks to everyone for their inputs on things, that really helps.

Iron

thanks to Chuck and DigiKey

Iron

thanks, great lecture !

Iron

thanks!  need more presenters like Paul

Iron

great!!!  thanks paul and chuck...

thanks Paul and Chuck, an interesting session today.

Iron

@SE, bobbybacs - Yeah on external reset, but the processor will just run to the same point and hard lock again.

Iron

Thanks Paul - great presentation

Iron

Thanks very informative lecteur

Iron

Thanks Paul and Chuck.

Iron

ext watchdog will avoid coding errors.  have done this when must reboot itself.  int watchdog can have common errors to source

 

Iron

while not M0 specific, would really appreciate coverage of the System Clocks & PLL 

Iron

use external watchdog timer on NMI or hard reset to ensure restart

Iron

of course an external watchdog will do it

Iron

again, offet count in bytes. looks like the cortex memory is organized as bytes and not 32bit words?

Iron

Yes, I have a hard faault. 

No prior experience with Cortex MCUs... which of course why I signed up for this seminar!

Iron

no - but I usually get the handler correct before significant application development.

will a watchdog timer save you from a lockup?

Iron

no experience with cortex yet, sounds like a handy feature though.

Iron

@Chuck: no, not on Cortex

Iron

hard faults yes M0/M3

 

Iron

@Paul: is there any watchdog timer available on Cortex-M0 ?

Iron

@chuck - no, haven't used Cortex devices

Iron

@chuck - have not experienced hard lockup

Iron

No hard fault or core lockup yet.

Iron

hardfault on cortex m3

Iron

Yup, too many times !

Iron

@batye - how can you have a maybe to a binary question??? :)

Sure, but savings highly dependent on tasks (application) running and peripheral usage.

Iron

Nothing on power saving measurements.

Iron

have not measured core power in cortex or any other processors

Iron

@chuck - have not worked with cortex power saving

Iron

nope but would be cool to try that

Iron

can the clock freq be dynamically changed?

 

Iron

@CONFIRM?:

WFI - Wait for int to wake up

WFE - Wait for int to wake up if another event occurs

Iron

@Chuck: have tried low power modes on other processors but found that the design needed a faster wakeup than was supported by the processor.

Iron

@dan -- used to live in Woodbine/Woodlands near Sarcee. Know it well.

Iron

What foundary/process/supply voltage is this current graph based on?

Iron

@DaveWR, could use some more climate warming here in Alberta.

Iron

Hello all from sunny North Carolina, Wilmington

Iron

used on an eval board

Iron

Currently my work is to test CPUIDLE, Suspend-Resume Features for OMAP processors

 

What is the Deep Sleep current?

have not used pwr saving mode

Iron

Have not used power saving. Doing my bit to warm the climate -- between that and my F150. ;-)

Iron

no power saving apps yet, but will become important with battery powered devices soon.

Iron

All I've done for power saving is keep the power off in unused peripherals.  Not using battery power and peripheral responses need to be very fast.

Iron

Don't remember.
Haven't done much assembler or microcontroller programming since 1991...

Iron

What's the difference between sleep and deep sleep?

 

Always do. We even go so far as to copy code to RAM and turn off the flash to save battery power when mains voltage goes down.

Iron

I used in all conception that I made. Batteries applications

not yet...but planning to do it in my nxt design

Iron

Device Specific - Yes

Core - Not yet

Have not needed to use power savings modes.

Iron

never used power savings, always had plenty of power

Platinum

@chuck - have not used power saving modes

Iron

Have not used Power Management opcodes

Iron

Used power saving modes in  a few designs.

Iron

Have not used power saving mode.

Iron

Never used power saving mode

Power saving very important.

Iron

@DaveWR, thanks. was thinking about being hammered by interrup requests and not getting back to the main code.

Iron

Q. What is differance between described instruction set and " Thumb instruction set " for cortex M0 ?

@dan lafleur -- my experience is that you won't get trapped on the interrupts -- I actually tested for this. ymmv -- all you can do is test.

Iron

Q; can the interrupt handler be trapped with late arriving interrupts with tail chaining?

Iron

hello from ottawa ontario

Iron

On the faster M3 Cortex and up it is said that it is best to clear interrupt at the beginning of the ISR. My experience is that it's is best as well.

fwiw

Iron

Hi all from California

Iron

Hi Paul,

Thanks for answering the question on low end micros.  I will be interested in finding the $0.25 USD Cortex micro.

Don

Iron
A little late but here.
Iron

hello from SUNNYN MIAMI.

 

Hi Chuck, Paul, and all.

Iron

If the rasio feed keeps saying Blog Talk Radio, press F5

Iron

@capstone, try browser refresh when audio loops

Iron

Central NY, USA Sunny 79 F

Iron

Good afternoon Paul.

Iron

Beautiful 85° in Boston

Iron

why is the radio feed looping?

 

Iron

Good afternoon folks.

Iron

I think we have most contents covered.

Hello from North Carolina, USA.

Iron

Hello from Richmond, TX.  88 degrees and supposed to rain.  (Still sunny)

Iron

Hello from Sweden.

Iron

Hello Paul and Chuck - looking forward to today's presentation

Iron

hello to all from Sonora, Calif!

 

 

Iron

Hi from cool (<70 F today) Portlandia

Hi from northern California

Iron

Paul,

I'd like to echo Don H's comment, and ask for more context.  I seem to detect an expectation, whether conscious or not, that your audience is conversant with other cortex processors and the ARM family in general (like an offhand comparison to ARM7 functionality).  I have done alot of embedded development and understand, for instance, how preemption is done, but I'd like the answers to questions like what are the features of the ARM and Cortex families which pertain to embedded development and what are the uses and applications for which they are intended?  Otherwise, it's been a useful presentation so far, and thanks for doing it.

Iron

Ft Worth, Texas Online !

Iron

Hello everyone, from Ontario Canada

Iron

Lets get the show on the road!

Iron

Hello from Johannesburg, South Africa...7h38 p.m.

Iron

Hello and GOOD Morning/Afternoon from Sunny San Jose CA. It's 68 °F and will peak @ 78 °F.

Iron

@Don H, there is one current uC that does not use interrupts. It's the Parallax Propeller chip. 8 32-bit cores @ 20MIPS each do all the work from 32K of shared RAM.

 

... just wanted to share this.

Iron

Good morning all from Edmonton, AB 19C/66F and overcast. It's still better than -40 with wind!

Iron

Hello Paul,

Thanks for presenting this, but could you help provide more insights on what differentiates the CORTEX?

I live in the 8 bit world and the presentations on interrupts are not unique.  I do not think there is a embedded controller out there that does not use interrupts.  The memory map is just another one with bigger numbers.

Our customers are only willing to pay more to get better functionality.  For example, there are lots of crock pots and rice cookers still using 4 bitters (yes, they still exist in high volume).  Why pay more unless it can do something?  In this example, what about starting the device from your smart phone?  That requires wireless, an ethernet stack + .  But a customer would like that feature.

Best regards,


Don

Iron

Hello form sinaloa mexico

Howdy folks!  Beautiful day in SW Missouri!   :)

Hello from Vancouver

Iron

Good afternoon from Sunny Lake Simcoe in Ontario Canada.

Iron

morning! 8;30 A.M.

Rod. R.

Iron

Logging in early so I don't miss it.

Iron


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