Electrical – How to make communication between microcontrollers

arduinocommunicationmicrocontrollerstm32

I want to make a project where it is necessary to communicate between several microcontrollers in the fastest way possible.

For that matter I have 10 micro-controllers whose names will be 1 … 10:

I want 1 to receive a number as input (input from user), and send it to 2.
2 will receive the number and will add 10 to it, and send the results to 3.
And so each will add a number and send the results to the next micro-controller until it reaches 10.

10 will output the final output (the output should be the number 1 received as input + all the numbers that the other processors in the chain added).

I am looking to buy STM32F103C8 (blue pill) because they look both cheaper and also stronger (and they looked more supported) than Arduino (although I am open to suggestions for other micro-controllers including claims in favor of Arduino).

Now my question is how I connect the micro-controllers I have selected (or the suggested micro controllers) to each other in the fastest and most efficient way.

I'm not looking for suggestions like: add an Ethernet/Bluetooth module and communicate with it between the micro-controllers.

I'm looking for an explanation of how to connect them using a serial or I2C connection or something like that (and I would be happy if you could add a detailed guide on how exactly to do it, which legs to attach to etc., since I'm still relatively new at working with micro-controllers)

Thank you.

Best Answer

The best way depends on exactly how much data do this microcontrollers have to communicate among them, the distances the signals have to travel, the place where this communication will take place, the amount of pins/wires you're willing to use to wire everything up, the cost of the system as regards your programming time and the hardware cost. For instance CAN bus allows for communication in noisy/industrial/automotive environments but is hard to implement and can't transfer data as fast as usb 3.0 does.

If I were you, and didn't have any stringent requirements for protocol implementation, I would consider the points I mentioned and end up with the easiest option as long as community support and hardware is concerned. Search for an easy to follow and comprehensive tutorial of a protocol readily available on the boards you're considering. Each protocol has it's pros and cons so it's not as if you would be better off learning how to implement one in particular.

As regards selecting one microcontroller, you seem to be looking for a readily assembled board. There's a huge selection to chose from, and many times the right board selection boils down to other capabilities than just having a communication protocol hardware built-in. The blue-pill board you're mentioning seems to be kind of the Arduino Due "equivalent" in terms of specs, check which board suits your needs best.

Related Solutions

Electronic – arduino – Selecting the right microcontrollers for this project (Arduino based)

Most small microcontrollers will be capable of doing what you need. You could even ditch the Arduino "wrapper" and use a USB capable micro in it's place.

Microchip, Atmel, TI, ST, etc all have 8, 16, 32-bit uCs of varying RAM/FLASH/EEPROM sizes to pick from. All the modern uCs come with at least UART, SPI, I2C peripherals that can be used for your communications.
There is not a lot in them really, I'd just pick one and see how you like it.
I (currently) use ST's 32-bit ARMs and Microchip 8, 16 ,32-bit PICs.
I'd probably use a few PIC12F or 16Fs for the slave uCs and a PIC18F or PIC24F for the master.

You mention needing ~10kbits of memory (not quite clear what type or which uC needs it from your description to me though)
It's easy to determine what is suitable though, just check the RAM/ROM/EEPROM specs of each uC you look at.
For example the PIC16F1938 has:

 Parameter Name          Value
 Program Memory Type     Flash
 Program Memory (KB)     28
 CPU Speed (MIPS)        8
 RAM Bytes               1,024
 Data EEPROM (bytes)     256

So 28KB of program memory is more than enough to store non-volatile data if your program is small enough (on the newer PICs you can also read/write to program memory at run time) 10kbits will not quite fit into the RAM though, at 1024 * 8 = 8192 bits.
The 16F1527 has 1536 bytes of RAM though, so you could use this if necessary.

For the master (alternatives to Arduino) there is something like the 18F25J50 or similar, which has a USB 2.0 peripheral. Microchip provide a USB stack an plenty of example firmware to get you started with USB.
If you need something more powerful for the master, have a look at the PIC24 series with up to 256K of Flash and 96K of RAM. Or even the PIC32 which is 32-bit and up to 80MIPS. The PICKit3 is a low price programmer that will program all the above mentioned PICs, and MPLAB (or MPLABX) is a free IDE for firmware development.

Communication can be done with I2C, which deals with the master/slave configuration and addressing easily. All you have to worry about is sending the data. 7 meters should be no problem with a reasonably quiet environment and the right setup (low value pullups - say 2.2k, low capacitance cable)

Electronic – Frequency modulation and communication between two microcontrollers

If you are just interessted in the microcontroller stuff I suggest to use pre-built transmitter and receiver modules (e.g. working at 433MHz frequency; look e.g. here) that can be easily interfaced to microcontrollers.

If you are interested in designing transmitters and receivers, this is a whole new field, a science of its own.

Best Answer

Related Solutions

Electronic – arduino – Selecting the right microcontrollers for this project (Arduino based)

Electronic – Frequency modulation and communication between two microcontrollers

Related Topic