Can i connect two or four 8bit microcontroller and make a...

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Hi guys!
I have a Interesting idea!
can i connect two or four 8bit microcontroller and make a 16bit or 32bit microcontroller? :)

"One's value is inherent; money is not inherent"

 

Chuck, you are in my heart!

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Sure! It's as easy as connecting several small cars in a row to get a large-Scale truck! Connecting the small cars in parallel will in turn get you a ferrari.

Einstein was right: "Two things are unlimited: the universe and the human stupidity. But i'm not quite sure about the former..."

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This is not a new idea : bit slice processors were somewhat popular in the late '70s (wikipedia bit_slicing can confirm it); however, they needed at least physical access to the overflow bit and the clock, have a mean to share program memory . As people complaining MCU do not have enough pins, and as it would need to add many pins, better ideas would be : to use 16 bits/ 32 bits processors , if needed (Texas has a very cheap 16 bit card -and a stellaris ARM 32 bits which is cheaper than Arduino-, ARMs is getting popular..)

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So, you say that i use a 16 or 32 bit, it's better?
Can i connect four tiny micro to a atmega32 to make a 32bit micro?
How to do?

"One's value is inherent; money is not inherent"

 

Chuck, you are in my heart!

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Nobody knows...
It would be cheaper to buy demo cards, such as STM32F0 discovery or Texas Stellaris Launchpad (already soldered) if you really need a 32 bit (both are cheaper than Arduini ) or to buy a Rapsberry Pi -kind of miniPC you may have to add a screen and a keyboard : connectics are not such good, to make prices very low.
The advantage of the STM32F0 is that it has a book (and links inside it) , and you will see it is ... more complex than AVRs (7 or 8 registers are needed to control a pin w/r to direction and value for old AVRs) www.cs.indiana.edu/~geobrown/boo...
(this free book explains succincltly the structure of their MCU, and gives intersting examples: but perhaps you should read good books dedicated to AVRs -and computer structure-, such as Smiley's one...

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One thing is certain: Making all your posts in bold typeface does not make you look more serious. You come through as a kid being loud to get attention.

-----

On the subject:

For cascading several 8-bit CPUs together, they'd need to expose e.g. carry bits on I/O pins - so that e.g. a 32-bit add can actually be done. Many similar requirements, that e.g. AVRs do not expose, can probably be listed in the hundreds.

The sharing of program memory that dbrion talks about will not really work. If you want to do a 32-bit addition, then the MCU dealing with the LSB should do an ADD (and expose the carry on an I/O pin to the next MCU), and the other three MCUs should do ADC (getting hte carry from the "previous" MCU, and exposing it's own carry on a pin to the "next" MCU). So the program memories wil have to have different contents. Also, there will be a timing issue, the MCU doing the second least significant byte ADC will have to wait until the MSU doing the least significant byte has produced it's carry. So clocs on the four MCU will have to be "interlaced".

Etc etc. The list or problems and obstacles is long.

All this is just mind-play. AVRs do not expose the things needed to do this.

If you want to deal with data larger than bytes, e.g. 32-bit integers, then AVRs can handle them just fine - but rather than parallelling operations they are sequwnced in one MCU. This of-course comes with an execution time cost.

If you need fast 32-bit operations then go for a 32-bit MCU. E.g. an ARM-based MCU.

As of January 15, 2018, Site fix-up work has begun! Now do your part and report any bugs or deficiencies here

No guarantees, but if we don't report problems they won't get much of  a chance to be fixed! Details/discussions at link given just above.

 

"Some questions have no answers."[C Baird] "There comes a point where the spoon-feeding has to stop and the independent thinking has to start." [C Lawson] "There are always ways to disagree, without being disagreeable."[E Weddington] "Words represent concepts. Use the wrong words, communicate the wrong concept." [J Morin] "Persistence only goes so far if you set yourself up for failure." [Kartman]

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Well, I just messed up 'overflow' and carry (both exist... just for additions. what about multiplications -that would be a terrible nightmare-?)

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I think you're totally overrunning the OP with things like carry bits rippling thru the individual cores and the like. From his latest post he seems to think that an ATmega32 is indeed a 32bit chip...

Einstein was right: "Two things are unlimited: the universe and the human stupidity. But i'm not quite sure about the former..."

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well, if Monsieur OP sends, through a serial line, data to be processed to a PC, he might have, with some luck and skills, a 32/64 bits coprocessor (but, if he puts ten PC one above the other, I bet the heap of PC wonot get a 320...640 bits machine..)

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Quote:

but, if he puts ten PC one above the other, I bet the heap of PC wonot get a 320...640 bits machine.

Then PCs, one on top of the other would make a stack, not a heap. :wink:

As of January 15, 2018, Site fix-up work has begun! Now do your part and report any bugs or deficiencies here

No guarantees, but if we don't report problems they won't get much of  a chance to be fixed! Details/discussions at link given just above.

 

"Some questions have no answers."[C Baird] "There comes a point where the spoon-feeding has to stop and the independent thinking has to start." [C Lawson] "There are always ways to disagree, without being disagreeable."[E Weddington] "Words represent concepts. Use the wrong words, communicate the wrong concept." [J Morin] "Persistence only goes so far if you set yourself up for failure." [Kartman]

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If you can buy a 16/32 bit micro for the same cost as an 8bit micro why would you even consider joining four 8bit micros to make 32bit (you can't by the way) and spend four times the money?

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Rohalamin wrote:
can i connect two or four 8bit microcontroller and make a 16bit or 32bit microcontroller? :)[/b]

There is no relation between CPU bit size and mathematics bit size.
E.g. the 8bit AVR-GCC provide libs for 32bit float and 64bit integer.
And in assembler you can do your own mathematics e.g. 1024bit wide.

The only limitation for mathematics size was the amount of SRAM.

To use several AVRs for higher mathematics was never an option.
Because the data transfer overhead was many times bigger, than the CPU load.

Last Edited: Thu. Mar 28, 2013 - 01:41 PM
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Quote:

And in assembler you can do your own mathematics e.g. 1024bit wide.

I can do that in C too - although I won't get the nice operands/operator syntax, but must rely on funtions. Enter C++ - now I get the operands/operator syntax back. :D

As of January 15, 2018, Site fix-up work has begun! Now do your part and report any bugs or deficiencies here

No guarantees, but if we don't report problems they won't get much of  a chance to be fixed! Details/discussions at link given just above.

 

"Some questions have no answers."[C Baird] "There comes a point where the spoon-feeding has to stop and the independent thinking has to start." [C Lawson] "There are always ways to disagree, without being disagreeable."[E Weddington] "Words represent concepts. Use the wrong words, communicate the wrong concept." [J Morin] "Persistence only goes so far if you set yourself up for failure." [Kartman]

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bc is written in C and can do in(de)finite arithmetics...
People who 'compute' a huge lot of PI's decimals program in C/C++ or in Fortran ...

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OP might want to look into Transputer and how the node communication is (was?) done there.

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.

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JohanEkdahl wrote:
One thing is certain: Making all your posts in bold typeface does not make you look more serious. You come through as a kid being loud to get attention.

-----

On the subject:

For cascading several 8-bit CPUs together, they'd need to expose e.g. carry bits on I/O pins - so that e.g. a 32-bit add can actually be done. Many similar requirements, that e.g. AVRs do not expose, can probably be listed in the hundreds.

The sharing of program memory that dbrion talks about will not really work. If you want to do a 32-bit addition, then the MCU dealing with the LSB should do an ADD (and expose the carry on an I/O pin to the next MCU), and the other three MCUs should do ADC (getting hte carry from the "previous" MCU, and exposing it's own carry on a pin to the "next" MCU). So the program memories wil have to have different contents. Also, there will be a timing issue, the MCU doing the second least significant byte ADC will have to wait until the MSU doing the least significant byte has produced it's carry. So clocs on the four MCU will have to be "interlaced".

Etc etc. The list or problems and obstacles is long.

All this is just mind-play. AVRs do not expose the things needed to do this.

If you want to deal with data larger than bytes, e.g. 32-bit integers, then AVRs can handle them just fine - but rather than parallelling operations they are sequwnced in one MCU. This of-course comes with an execution time cost.

If you need fast 32-bit operations then go for a 32-bit MCU. E.g. an ARM-based MCU.


Hi johan!
I'm not a kid! why you flout to me?
Your note is very good and complete. i just interest to bold write. in end, i'm very thanks to you.

"One's value is inherent; money is not inherent"

 

Chuck, you are in my heart!

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DO1THL wrote:
I think you're totally overrunning the OP with things like carry bits rippling thru the individual cores and the like. From his latest post he seems to think that an ATmega32 is indeed a 32bit chip...

This just was an idea!
We know that an atmega32 is a 8bit microcontroller. :wink:

"One's value is inherent; money is not inherent"

 

Chuck, you are in my heart!

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μnix
Quad XMEGAs.
May not be active.

"Dare to be naïve." - Buckminster Fuller

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clawson wrote:
If you can buy a 16/32 bit micro for the same cost as an 8bit micro why would you even consider joining four 8bit micros to make 32bit (you can't by the way) and spend four times the money?

Hi claw!
are you sure that cost of an 8bit micro as a 16/32 bit micro?
How to Compare?
please put a link to show this subject.

"One's value is inherent; money is not inherent"

 

Chuck, you are in my heart!

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danni wrote:
Rohalamin wrote:
can i connect two or four 8bit microcontroller and make a 16bit or 32bit microcontroller? :)[/b]

There is no relation between CPU bit size and mathematics bit size.
E.g. the 8bit AVR-GCC provide libs for 32bit float and 64bit integer.
And in assembler you can do your own mathematics e.g. 1024bit wide.

The only limitation for mathematics size was the amount of SRAM.

To use several AVRs for higher mathematics was never an option.
Because the data transfer overhead was many times bigger, than the CPU load.

AWooo!
:?

"One's value is inherent; money is not inherent"

 

Chuck, you are in my heart!

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JohanEkdahl wrote:
Quote:

And in assembler you can do your own mathematics e.g. 1024bit wide.

I can do that in C too - although I won't get the nice operands/operator syntax, but must rely on funtions. Enter C++ - now I get the operands/operator syntax back. :D

Very cool! :lol:
so, no necessary to join four micro or buy a 16/32 or maybe 1024bit micro!

"One's value is inherent; money is not inherent"

 

Chuck, you are in my heart!

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dbrion0606 wrote:
bc is written in C and can do in(de)finite arithmetics...
People who 'compute' a huge lot of PI's decimals program in C/C++ or in Fortran ...

Thanks dbrion0606 for answer!
merci! :D

"One's value is inherent; money is not inherent"

 

Chuck, you are in my heart!

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Quote:

clawson wrote:
If you can buy a 16/32 bit micro for the same cost as an 8bit micro why would you even consider joining four 8bit micros to make 32bit (you can't by the way) and spend four times the money?

Hi claw!
are you sure that cost of an 8bit micro as a 16/32 bit micro?
How to Compare?
please put a link to show this subject.


https://www.avrfreaks.net/index.p...
https://www.avrfreaks.net/index.p...

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.

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theusch wrote:
Quote:

clawson wrote:
If you can buy a 16/32 bit micro for the same cost as an 8bit micro why would you even consider joining four 8bit micros to make 32bit (you can't by the way) and spend four times the money?

Hi claw!
are you sure that cost of an 8bit micro as a 16/32 bit micro?
How to Compare?
please put a link to show this subject.


https://www.avrfreaks.net/index.p...
https://www.avrfreaks.net/index.p...

thanks guy

"One's value is inherent; money is not inherent"

 

Chuck, you are in my heart!

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theusch wrote:
Quote:

clawson wrote:
If you can buy a 16/32 bit micro for the same cost as an 8bit micro why would you even consider joining four 8bit micros to make 32bit (you can't by the way) and spend four times the money?

Hi claw!
are you sure that cost of an 8bit micro as a 16/32 bit micro?
How to Compare?
please put a link to show this subject.


https://www.avrfreaks.net/index.p...
https://www.avrfreaks.net/index.p...

https://www.avrfreaks.net/index.p...
and specifically:
https://www.avrfreaks.net/index.p...

Not only does that show 32 bit for similar price to 8 bit but for the same money getting far far more resources. 64MHz, 64K flash, 16K RAM compared to 20MHz, 16K flash, 1K RAM for a few cents less.

Did you try searching yourself? There's tons of threads on this board comparing AVR8 to 32bit, principally Cortex and such threads generally all conclude that you get far more ARM than AVR for your money and even most of the $20 boards for them even include a JTAG debugger while for AVR the Dragon costs $50 alone.

So the basis of this thread does not make much sense when you can easily work with 32 bit anyway.

BTW as moderator I've edited your posts to remove the bold tags, please stop doing it as it's just a pain to do all the editing.

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"can i connect two or four 8bit microcontroller and make a 16bit or 32bit microcontroller? "

No, but you can buy 32-bit 50+ Mhz ARM microcontrollers for less than $10 and their development boards for about $25. These are all very small outline devices so you won't be soldering them yourself to a protoboard or testing circuits on a press-the-parts-into-white-plastic-holes breadboard.

64-bit multi-core semi-parallel quad processors have development boards pre-made by the millions. They cost about $100 for good state-of-the-art multi-GigaHertz system designs that use standard peripherals. Google for 'PC motherboards'.

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clawson wrote:
theusch wrote:
Quote:

clawson wrote:
If you can buy a 16/32 bit micro for the same cost as an 8bit micro why would you even consider joining four 8bit micros to make 32bit (you can't by the way) and spend four times the money?

Hi claw!
are you sure that cost of an 8bit micro as a 16/32 bit micro?
How to Compare?
please put a link to show this subject.


https://www.avrfreaks.net/index.p...
https://www.avrfreaks.net/index.p...

https://www.avrfreaks.net/index.p...
and specifically:
https://www.avrfreaks.net/index.p...

Not only does that show 32 bit for similar price to 8 bit but for the same money getting far far more resources. 64MHz, 64K flash, 16K RAM compared to 20MHz, 16K flash, 1K RAM for a few cents less.

Did you try searching yourself? There's tons of threads on this board comparing AVR8 to 32bit, principally Cortex and such threads generally all conclude that you get far more ARM than AVR for your money and even most of the $20 boards for them even include a JTAG debugger while for AVR the Dragon costs $50 alone.

So the basis of this thread does not make much sense when you can easily work with 32 bit anyway.

BTW as moderator I've edited your posts to remove the bold tags, please stop doing it as it's just a pain to do all the editing.


aoooo!
why i don't write bold?
It's not fair. Anyway, i respect to your law.although, no relation!

"One's value is inherent; money is not inherent"

 

Chuck, you are in my heart!