Electronics > Projects, Designs, and Technical Stuff

How to manage 120*8*16 microcontrollers?

<< < (3/4) > >>

Siwastaja:
Yes, I agree with ogden in the idea that if the firmware for the "node" is really super simple enough, it's fine to prototype the software once and then mass program.

If it's <100 lines, configuring ADC and SPI, or possibly bitbanging a simple control interface, then chances that there is a hard-to-find, hidden bug left after initial development is small. It's nonzero, but you can take the controlled risk.

I have been pushing my luck to >1000 lines of code, more complex distributed designs and have been quite succesful, but yeah, I understand it's a bit scary.

But if a cheap SPI ADC does the job, I wouldn't go this way just to save some cents; the price difference isn't that much. OTOH, if the SPI ADC doesn't somehow produce the wanted datastream format, for any reason, then an MCU replacement quickly becomes attractive.

Those On-Time-Programmable cheap Chinese controllers would be spot-on. Yes, there is a risk, but also learning opportunities.

JohanHoltby:
Wow. Such great thoughts from all! THANK YOU! I have done some more thinking after reading your thoughts and will go with a larger singel chip IC like STM32F3... There is some which have 4 ADCs with 5Msps which would reduce the complexity very much.


--- Quote from: OM222O on June 02, 2019, 12:18:07 pm ---call me crazy but at a lot of places you can't get more than Gigabit internet ... your application requires 2 10Gbit connections.

--- End quote ---
& and many more.
Yes that would be crazy. That is why I use the memory. I want to be able to break the system and evaluate what the **** happened.
The bus speed only need to be about 500kbit/s when the data is fetch out from the system. I'm leaning to RS485 right now. Good or bad?


--- Quote from: Siwastaja on June 02, 2019, 02:47:13 pm ---For such systems, it's not a bad idea to use distributed simple serial (SPI, for example) ADCs, and use a large FPGA....

--- End quote ---
This is a cost constraint. The SPI ADCs cost more than a MCU. But as other have pointed out I will run in to problem if i try to program them before i place them if when I find a bug. JTAG might be an option if I use the STM chip maybe?...


--- Quote from: mikeselectricstuff on June 02, 2019, 03:02:33 pm ---BTW you can get 64Mbit SPI SRAMs, which will be much easier to drive than SDRAM :
https://lcsc.com/product-detail/RAM_VTI7064MSME_C139966.html

--- End quote ---
Great I will keep them in mind for the future. They was quite costly but definitely interesting if I would go with a single MCU for every function. That is no longer the case due to the feed back I have received. I still have the challenge of using only 3.3V RAM chips. Most in lower voltage especially the ones cost less.


--- Quote from: coromonadalix on June 02, 2019, 02:37:03 pm ---And  as other replied, why do you need to measure up to 1ms/sec  ???  is it too critical ??

--- End quote ---
No 1ms/sec is not critical and it's not a hard constraint but it would be nice to know what did happened in the system and when.

jmelson:
I just designed a 512-channel power supply to bias silicon photomultipliers.  Each needs a slightly different voltage to give the correct gain.  We also wanted current readout.

So, this thing will have 512 channels of DACs to set the voltage, and 512 channels of ADCs to read the current.
I did this all with ONE computer, a Beagle Bone Black.  Due to the large amount of channels, I used the PRU (200 MIPS microcontroller) to do the low-level I/O.  This is not fast sampling, but can read all the channels in a few milliseconds.

If I understand your subject line correctly, you are talking about using 15,360 microcontrollers?  YIKES!

Jon

chris_leyson:
If you put a small micro onto an FPGA then from Xilinx KCPSM6 user guide
--- Quote ---By the way, the current record stands at 3,602 in an XC7V2000T and it wasn’t full 
--- End quote ---
. State machines would be more economical for this application.

JohanHoltby:
:) I have got so much bash I will not go there (thankfully). I will use only some higher lever higher speed MCUs. My current plan is STM32G3 or STM32F3 and use about 4 per board. As you indicated my original plan would have given me some headache.

Navigation

[0] Message Index

[#] Next page

[*] Previous page

There was an error while thanking
Thanking...
Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod