microcontroller networking

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What SICK man network fourteen 8-bit AVRs?

<
https://www.youtube.com/watch?v=Y-CRYJ8_Kf0


The related project looks very interesting:

<https://github.com/gioblu/PJON

I'm experimenting with using (smaller) clusters of 8-bitters for  
low-power processing/splitting a single UART input, that's sending large  
amounts of serial data from one input into multiple serial outputs but  
where not all of them might be in use at any one time, or one output  
needs a lot of processing done at a given time but the others aren't  
sending much. so you might be able to have two or more processors  
collaborate.

Sort of like those V8s that can shut down cylinders when highway  
cruising and V8 power not required.

I don't know yet if this will have any actual power savings/cost  
advantage to using one big fuck-off fast ARM to do everything but is
fun to experiment with.

Most ARMs don't have the required number of UARTs on board for output  
anyway so you'd have to buy some i2c to multi-UART bridge chips or  
something if you want niceities like hardware FIFO buffering and they  
tend to be expensive, more expensive than an 8 bitter with its own  
onboard UART. and they tend to come from Maxim...

Re: microcontroller networking

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Use an SOC, like a ZYNQ or one of the new cheaper ones, and roll as
many uarts as you have pins to spare.


--  

John Larkin         Highland Technology, Inc

lunatic fringe electronics  


Re: microcontroller networking
On 02/16/2019 11:25 AM, John Larkin wrote:
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what's the price break on those? Dunno if I have the budget for it.  
ARM-9 seems like overkill for the job....

These OTP mixed-signal FPGA-things look neat I believe Apple is using  
them now for doing in-house battery management-stuff. They're cheap  
maybe 25-50 cents in quantity for the lower-end models and might have  
enough logic on board to do a poor man's i2c-UART. they have memory.  
they got a user-definable state machine.

<https://www.dialog-semiconductor.com/configurable-mixed-signal

Re: microcontroller networking
On 02/16/2019 11:37 AM, bitrex wrote:
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I don't need multiple inputs, just i2c to FIFO-buffered outputs, ideally.

Re: microcontroller networking
On Saturday, February 16, 2019 at 11:37:35 AM UTC-5, bitrex wrote:
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They have very limited logic capability.  It would have to be a very simple function you are programming and I'm pretty sure they can't do i2c-UART unless you find one with both built in.  Only a couple of versions have in system programmability.  

Rick C.  

Re: microcontroller networking
On 02/16/2019 11:21 AM, bitrex wrote:
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To clarify yes battery operation is a requirement. AA cells, probably.

Re: microcontroller networking
On 16.2.19 18:21, bitrex wrote:
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Years ago, I made a board consisting of 27 ATMega's networked with
one more ATMega, using SPI as multi-master bus.

Every slave had a flash chip along, and the whole thing was used for
production flashing of a batch of 27 target controller boards at a time.
The flash chip contained the code to download.

--  

-TV


Re: microcontroller networking
On Sat, 16 Feb 2019 19:26:30 +0200, Tauno Voipio

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Beats my best of 13 cpu's on a VME board.

https://www.dropbox.com/s/6vqwmng3lq8ev3z/V220_board.jpg?raw=1

(12 of mine are electrically isolated from ground. Each is a floating
4-20 mA i/o/dac/dvm channel.)


--  

John Larkin         Highland Technology, Inc

lunatic fringe electronics  


Re: microcontroller networking
On 2/16/19 12:26 PM, Tauno Voipio wrote:
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I guess you had pissed off your boss. ;)

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Cheers

Phil Hobbs


--  
Dr Philip C D Hobbs
Principal Consultant
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Re: microcontroller networking
On 16.2.19 23:45, Phil Hobbs wrote:

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Actually not. It was my customer asking for the 28 processor
behemoth, and I was my own boss then (now retired).

--  

-TV

Re: microcontroller networking
14000 MCUs

https://youtu.be/ojfXOPazrKA

Re: microcontroller networking
On Saturday, February 16, 2019 at 1:00:13 PM UTC-5, Lasse Langwadt Christensen wrote:
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That's a pretty cool project.  

Rick C.  

Re: microcontroller networking

il.com:
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ensen wrote:
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Mike has done quite a few cool projects,  



https://www.youtube.com/user/mikeselectricstuff/




Re: microcontroller networking
On 2/16/19 3:35 PM, Lasse Langwadt Christensen wrote:

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https://www.youtube.com/user/mikeselectricstuff/

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+1

He used to be a semi-regular poster here.

Cheers

Phil Hobbs

--  
Dr Philip C D Hobbs
Principal Consultant
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Re: microcontroller networking
On 02/16/2019 01:00 PM, Lasse Langwadt Christensen wrote:
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My goals are more modest by a longshot but yeah, if I need say eight  
UARTs the ATTiny414 is 39 cents each in quantity how do I get hardware  
UARTs much cheaper than that. I don't think an ARM core with 8 UARTs is  
going to be as cheap.

And then if the processing requirements are fairly modest why do I need  
an ARM at all let the "UARTs" do the data crunching, too

Re: microcontroller networking
On a sunny day (Sat, 16 Feb 2019 17:02:07 -0500) it happened bitrex

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It would be a good thing for all those who want chips with many UARTs
to learn to do those in software.
Same goes for SPI and I2C.
But then maybe 'see' is not the prefered language, asm makes more sense.

For example I use software UART many times and never even use hardware
SPI or I2C, not even on any platform.

Re: microcontroller networking
On 02/17/2019 03:21 AM, snipped-for-privacy@nospam.org wrote:
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Sure, you can bit-bang serial, even pretty fast serial nowadays. But if  
you need 4, 8, 16 etc. serial outputs at a pretty fast rate it would  
seem that eventually your mpu ends up spending a lot of its time  
bit-banging serial.

If you want tight timing you have to have timer interrupts and every  
time a timer interrupt for one of the virtual output ports fires stop  
everything you're doing, do a context-switch, service the ISR, fiddle  
the bits, restore state, etc. it's not a particularly low overhead solution.

Also from a given MPU master clock not every baud rate is easily  
available to good accuracy from a nice rational-number-coefficient  
divide-down from the master clock.

Re: microcontroller networking
On Sunday, February 17, 2019 at 10:57:02 AM UTC-5, bitrex wrote:
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s
d
.
  
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on.

I'm not sure a "software UART" has to be so labor intensive.  If all the se
rial ports are at the same bit rate you can simply set a single interrupt f
or your sampling factor (say 8x bit rate) and read all the inputs in one wo
rd at the same time.  Some DMA units would be able to read this automatical
ly even reading a burst of enough samples to process a bit per burst.  Then
 it is a matter of the software sorting through the data to accumulate bits
 into framed characters, characters into messages, etc.  

Assuming you can read 32 inputs in one operation collecting each bit would  
be a matter of an 8 sample DMA.  

Yeah, the software would be interesting to do this way, but you don't seem  
to want to consider how easy software UARTs can be.  I'm not a big proponen
t of using Interrupts on MCUs because of the way they get complex fast with
 different priorities, etc, but multiple UARTs are a lot simpler than you s
eem to want to think they are.  

I was just researching the FPGA options and there are viable FPGAs for just
 over a dollar in QFN packaging.  I have to refresh my recollection periodi
cally so I can keep up with how inexpensive these things really are.  Oh ye
ah, this part has a hard I2C and SPI interfaces built in so you only need t
o design the UART and connection logic.  

Rick C.

Re: microcontroller networking
On 02/17/2019 12:33 PM, snipped-for-privacy@gmail.com wrote:
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Sure, for that price if you have suggestions I'm all ears...

Re: microcontroller networking

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A uart will work with a clock rate 8x the baud rate. So for 9600 baud
you could use a periodic interrupt of 76.8 kHz. That's no big deal
these days. The ISR could do, say, 16 UART i/o channels, given
reasonably efficient code.




--  

John Larkin         Highland Technology, Inc

lunatic fringe electronics  


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