networking STM32s

[drobison]

Posted on January 08, 2013 at 20:31

I have a question.  I need to connect 2 to 6 STM32s together.  I have motors I need to collectively control with a human machine interface.  Each motor will be controlled by one STM32.  The HMI also needs a STM32.  The HMI panel STM32 chip can be a master if necessary.  Which is the best way to allow the chips to communicate together.  Another issue is that they need to be isolated from each other. 

I was considering SPI, but that leads to 4 channels that need to be isolated.  I then thought about UARTs, but then I run into addressing and collision problems.  How would you do it?  Is there something I have not considered?  I considered CAN but the isolation requirement makes that unappealing.

#uart-spi-can-stm32-network

[jj2]

Posted on January 08, 2013 at 20:46

The distance between master and each slave controller/motor assembly likely will impact.  Suggest that you consider RS485 - which uses differential signalling for (relatively) long distance (>1000 ft. or more) control/communication.  RS-485 accommodates multiple units on the bus - and can employ a relatively eased, ''collision detection & prevention.''

Suspect that several vendors produce RS-485 ICs w/ in-built isolation you seek...

[frankmeyer9]

Posted on January 08, 2013 at 21:29

Suggest that you consider RS485 ...

 

I would suggest this, too.

Apart from being relative simple on the software side (UART), you have a wide range of possible data rates, to adapt to your needs.

As an example, the ProfiBus interface of the Siemes S5/S7 is also based on RS485.