networking STM32s

drobison · ‎2013-01-08

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 · ‎2013-01-08

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 · ‎2013-01-08

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.