Is EtherCat on STM32F207 and RMII (LAN8742) possible?

[machinist]

I am currently starting to investigate the possibility to run the Ethercat natively (without sub processor) on an STM32F207 (running at 120 MHz) with RMII. It is supposed to be a motorcontrol application that also runns a 16 KHz control interrupt to regulate the velocity.

As I see it so far I am trying to implement two realtime applications that do not tollerate any time offset.

So simply asked: is it possible to do this (in C and not assembler)? Or is it generally done with a dedicated subprocessor.

[T B]

EtherCat slave or master?

slave is difficult (impossible), because of the on the fly EtherCAT Communication

• Process data is extracted and inserted on the fly

[machinist]

Thanks for the replie. Its a slave.

[Ozone]

AFAIK, this is correct.

You would need an ASIC from Beckoff, implementing the slave access point.

[machinist]

Does anyone have experience with implementing ProfiNet directly on the STM32. It seems that it is based on standard TCP/IP.

My problem is just the 16 KHz control routine that musst run precisly and should rather not be interrupted for to long. I am not sure if this is even possible to run both the motorcontrol and the communication both in realtime on the same device. How is this generally solved? Is always a ASIC used (like the Beckhoff)?

Thanks!

[Piranha]

Synchronization

PROFINET IRT uses the transparent clock mechanism to synchronize PROFINET IRT devices. The transparent clock mechanism is specified in IEEE 1588-2008 (1588 V2). This creates one control loop between the master clock and slave clocks.

STM32 ETH peripheral supports IEEE 1588-2008 and is able to output recovered clock. Although it's not a typical clock... Look for more details in reference manual. Also a timer can be connected to that clock. Most likely Your motor control clock would have to be somehow based on that clock.