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 Posted: Jan 15, 2012 - 10:32 PM |
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Joined: Oct 30, 2002
Posts: 5720
Location: The Netherlands
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| in real application, there are likely more devices than just the MCU, so that adds to the energy consumption. |
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Posted: Jan 15, 2012 - 11:09 PM |
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Joined: Sep 12, 2009
Posts: 2398
Location: Sacramento, CA
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jan_dc wrote:
kk6gm wrote:
jan_dc wrote:
This is funny question IMHO. Of course the 8-bit MCU market is not destroyed and certainly not by ARM.
Why? The answer is simple: why should I use a 32 bit micro controller with way to much RAM/ROM when I don't need it?
But what if all that unnecessary RAM/ROM came on a chip that still cost less? Surely you wouldn't buy the more expensive chip just because it was 8 bits, or had less RAM/ROM, any more than you'd buy a 6.3v 0603 cap that cost more than a 10v 0603 cap, because you didn't need a 10v cap.
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In our applications we run a 8-bit MCU at 1.8MHz. The MCU market is way bigger than all the 'heavy' application which need high speed MCU's. People tend to forget that there is a world outside their own designs...
There's no penalty in running a fast micro slowly.
ok, I was a bit unclear I'm afraid. I'm not talking about mega and xmega cores. I'm talking about tiny stuff. Of course if a 32 bit fits the job and is cheaper, I'll use that. Haven't found any 32 bit yet that is overall cheaper.
OK, understood. I think price tracks IO count as much or more than 8/32 bit core. And I wouldn't claim that 32 bit will replace 8 bit, as much as that 8 bit will become more and more a niche market where extremely low cost, or low power, or low something else, override other concerns. And those applications will always be in a minority. |
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Posted: Jan 15, 2012 - 11:11 PM |
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Joined: Sep 12, 2009
Posts: 2398
Location: Sacramento, CA
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MBedder wrote:
LPC1111 is $2 retail, $0.88 in 1000s.
Just designed my first one into an application, based on price and the copious timer capabilites. |
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Posted: Jan 15, 2012 - 11:43 PM |
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Joined: Feb 09, 2011
Posts: 322
Location: Turnhout, Belgium
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kk6gm wrote:
jan_dc wrote:
kk6gm wrote:
jan_dc wrote:
This is funny question IMHO. Of course the 8-bit MCU market is not destroyed and certainly not by ARM.
Why? The answer is simple: why should I use a 32 bit micro controller with way to much RAM/ROM when I don't need it?
But what if all that unnecessary RAM/ROM came on a chip that still cost less? Surely you wouldn't buy the more expensive chip just because it was 8 bits, or had less RAM/ROM, any more than you'd buy a 6.3v 0603 cap that cost more than a 10v 0603 cap, because you didn't need a 10v cap.
Quote:
In our applications we run a 8-bit MCU at 1.8MHz. The MCU market is way bigger than all the 'heavy' application which need high speed MCU's. People tend to forget that there is a world outside their own designs...
There's no penalty in running a fast micro slowly.
ok, I was a bit unclear I'm afraid. I'm not talking about mega and xmega cores. I'm talking about tiny stuff. Of course if a 32 bit fits the job and is cheaper, I'll use that. Haven't found any 32 bit yet that is overall cheaper.
OK, understood. I think price tracks IO count as much or more than 8/32 bit core. And I wouldn't claim that 32 bit will replace 8 bit, as much as that 8 bit will become more and more a niche market where extremely low cost, or low power, or low something else, override other concerns. And those applications will always be in a minority.
Correct. For our applications peripherals and a large ROM (and/or EEPROM) are important. Speed is not important. Price is important of course and some other parameters such as having a free/cheap compiler/debugger.
It'll all change of course. But you can't say that the current 8-bit market is overthrown by ARM 32 bit cores. |
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Posted: Jan 15, 2012 - 11:58 PM |
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Joined: Nov 02, 2009
Posts: 3239
Location: Zelenograd, Russia
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Will resistors destroy a capacitor market?  |
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Warning: Grumpy Old Chuff. Reading this post may severely damage your mental health.
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Posted: Jan 16, 2012 - 09:19 AM |
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Joined: Dec 16, 2005
Posts: 3086
Location: Bratislava, Slovakia
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abcminiuser wrote:
Who knows what we'll all be using in 10 years time, if the software tools catch up to the device complexity.
Oh, yes.
The tools are complex enough now...
JW |
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Posted: Jan 16, 2012 - 12:45 PM |
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Joined: Oct 05, 2006
Posts: 2242
Location: Poland
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MBedder wrote:
LPC1111 is $2 retail, $0.88 in 1000s.
STM8S beats the price over twice!
http://www.avrfreaks.net/index.php?name ... p;t=113998
leon_heller wrote:
Then there is energy harvesting, for which very low power is desirable.
Then 20nA is an advantage only when it harvests 40nA-20nA=20nA, about this quantity is left (there is no point considering 20nA leakage as practical when the application harvests 1uA or more). Apart from the lack of energy storage with such small leakage (I do not think even a polypropylene capacitors would be of any use then) how do you imagine playing with a device with a budget of ~1,7mAh after 10 years of harvesting?
Either you got caught on a catchy tune of Brand X, or there is a technology/market I am not aware of.
Again: Could you post a link to some reference design (with a basic budget calculation) to show me/us any practical use of 20nA (or even 100nA) power-down current (by "practical" I mean that the lower power-down current in a general purpose (not asic) microcontroller reduces BOM of some design more than, lets say, 10%, w.r.t. the Brand N having 200uA leakage)?
Sorry for asking again, but you are repeating the Brand X marketing slogan all over again, instead of answering to my question. I am sure that at some point in the future there will be 5mAh, 0805 primary cells lasting 20 years, 1 cent in 1k quantity, but AFAIK this is not happening now. |
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Posted: Jan 16, 2012 - 12:51 PM |
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Joined: Nov 02, 2009
Posts: 3239
Location: Zelenograd, Russia
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Brutte wrote:
STM8S beats the price over twice!
Since when the STM8S has became a 32-bitter? |
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Posted: Jan 16, 2012 - 01:18 PM |
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Joined: Jul 27, 2001
Posts: 7429
Location: St. Leonards-on-Sea (UK)
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Brutte wrote:
MBedder wrote:
LPC1111 is $2 retail, $0.88 in 1000s.
STM8S beats the price over twice!
http://www.avrfreaks.net/index.php?name ... p;t=113998
leon_heller wrote:
Then there is energy harvesting, for which very low power is desirable.
Then 20nA is an advantage only when it harvests 40nA-20nA=20nA, about this quantity is left (there is no point considering 20nA leakage as practical when the application harvests 1uA or more). Apart from the lack of energy storage with such small leakage (I do not think even a polypropylene capacitors would be of any use then) how do you imagine playing with a device with a budget of ~1,7mAh after 10 years of harvesting?
Either you got caught on a catchy tune of Brand X, or there is a technology/market I am not aware of.
Again: Could you post a link to some reference design (with a basic budget calculation) to show me/us any practical use of 20nA (or even 100nA) power-down current (by "practical" I mean that the lower power-down current in a general purpose (not asic) microcontroller reduces BOM of some design more than, lets say, 10%, w.r.t. the Brand N having 200uA leakage)?
Sorry for asking again, but you are repeating the Brand X marketing slogan all over again, instead of answering to my question. I am sure that at some point in the future there will be 5mAh, 0805 primary cells lasting 20 years, 1 cent in 1k quantity, but AFAIK this is not happening now.
It's a new technology and a new market for 8-bit devices. The applications will start to appear now that suitable MCUs are available. |
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Leon Heller
G1HSM
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Posted: Jan 17, 2012 - 02:07 AM |
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Joined: Feb 13, 2007
Posts: 1025
Location: Gillies, Ontario
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Posted: Jan 17, 2012 - 02:16 AM |
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Joined: Oct 15, 2005
Posts: 530
Location: Russia, Far East Siberia, Irkutsk
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MBedder wrote:
Brutte wrote:
STM8S beats the price over twice!
Since when the STM8S has became a 32-bitter?
You mean 48-, 64- or 128-bit? |
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Posted: Jan 17, 2012 - 02:53 AM |
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Joined: Feb 09, 2011
Posts: 322
Location: Turnhout, Belgium
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AtomicZombie wrote:
I can still purchase 74 logic DIP parts.
... just sayin!
We still use them... |
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Posted: Jan 17, 2012 - 08:50 AM |
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Joined: Sep 05, 2001
Posts: 2496
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I like the small AVRs.
They have lots of advantages in comparison to ARM, e.g.:
- small pin count (6, 8, 14, 20, ..)
- easy to solder
- wide VCC range (1.8 - 5.5V), no regulator needed.
- internal clock and brown out reset
- easy hardware, no external components needed
- easy initialisation (software)
The ARM has advantages only on bigger projects, e.g. with GUI, Ethernet, Filesystem and so on.
Peter |
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Posted: Jan 17, 2012 - 10:14 AM |
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Joined: Jul 18, 2005
Posts: 62257
Location: (using avr-gcc in) Finchingfield, Essex, England
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Peter,
Just hypothetical but if you were paying say $0.80 for the AVR chips and then an ARM that offered pretty much the same for $0.50 appeared would you switch?
Cliff |
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Posted: Jan 17, 2012 - 10:42 AM |
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Joined: Sep 05, 2001
Posts: 2496
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clawson wrote:
Just hypothetical but if you were paying say $0.80 for the AVR chips and then an ARM that offered pretty much the same for $0.50 appeared would you switch?
No, because the CPU cost was irrelevant.
If I need a more complex pcb and more external components around the CPU,
then the ARM was many more expensive in the sum.
Also it's easier to solder SOIC8 instead LQFP100.
But I miss more AVR with CAN, e.g. something like:
- ATtiny84CAN
- ATmega328CAN
Peter |
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Posted: Jan 17, 2012 - 10:46 AM |
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Joined: Nov 02, 2009
Posts: 3239
Location: Zelenograd, Russia
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danni wrote:
ATmega328CAN
What's wrong with Mega32M1 then? |
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Posted: Jan 17, 2012 - 10:55 AM |
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Joined: Oct 04, 2008
Posts: 410
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clawson wrote:
Peter,
Just hypothetical but if you were paying say $0.80 for the AVR chips and then an ARM that offered pretty much the same for $0.50 appeared would you switch?
Cliff
Sorry to interrupt... but do you realise the cost of grabbing this $0,30 advantage? Suppose your working place costs $100 or $200/h. Your pennywise choice affects many other people in your company. Also you have to make design changes.
Change costs (a LOT of) money. Conservatism often pays better.
It happened many years ago, but I still feel ashamed of having a stupid little plastic part on my drawing board for more then a month because this kind of cent discussions. |
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Posted: Jan 17, 2012 - 11:25 AM |
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Joined: Jul 18, 2005
Posts: 62257
Location: (using avr-gcc in) Finchingfield, Essex, England
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Quote:
Sorry to interrupt... but do you realise the cost of grabbing this $0,30 advantage?
Suppose you make 2 million units per year (my old company did - and that was just one of several products). Then 2,000,000 * $0.30 = $600,000. So, yes, we would most definitely change micro if we could take $0.30 out of the bill of materials by doing so! Heck, we used to change capacitors if it would save $0.01 or even less. |
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Posted: Jan 17, 2012 - 11:35 AM |
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Joined: Oct 04, 2008
Posts: 410
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I know you are very clever. So please show us a frequency distribution graph of the series quantity of electronic products. I mean: how many products are there made in 2,000,000 series compared to series of 1, 10, 100, 1000 and so on.
I think there will be many, many more designs realised in small quantities. |
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Posted: Jan 17, 2012 - 12:02 PM |
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Joined: Sep 05, 2001
Posts: 2496
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MBedder wrote:
What's wrong with Mega32M1 then?
Still hard to get it (not on stock at Mouser, Farnell, RS, ...).
We need only small quantity.
Thus we use for new projects still the old AT90CAN128, which was good available from many distributors.
But I miss some features (UARTs as buffered SPI, pin change interrupts).
Peter |
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