I need to control about 50-motors(brush DC/Stepper) with each of them having an encoder for feedback.Precise motion control is needed for each motor axis.I have been looking at ARM cortex-M4 microcontrollers for this purpose.The ARM website mentions that Cortex-R series would be more suitable as it is designed for hard-real time applications like these.

However, i couldn't find any resources for getting started with Cortex-R series, particularly Cortes-R7 or R8.There don't seem to be any development boards either.Could some one point me in the right direction or give any suggestions about which controller to use here.


closed as off-topic by Dmitry Grigoryev, Michael Karas, Leon Heller, Enric Blanco, old_timer May 22 '17 at 17:19

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  • \$\begingroup\$ The Cortex-R series is more about safety-critical applications; Cortex-M can do hard realtime just as well. \$\endgroup\$ – Abe Karplus May 22 '17 at 10:22
  • \$\begingroup\$ VTC - This is an off topic question asking for advice on sourcing recommendations on a specific application. \$\endgroup\$ – Michael Karas May 22 '17 at 10:31
  • \$\begingroup\$ The cortex-r is about having two cores and if they dont agree then do something. What you run on it is up to you, and you can use other processors that dont have the redundancy (and/or make the redundancy yourself), there are the ti launchpads with cortex-rs and a myriad of cortex-m boards out there from ti, st and others \$\endgroup\$ – old_timer May 22 '17 at 17:04
  • \$\begingroup\$ www.design-reuse.com/articles/26106/cortex-r-versus-cortex-m.html dont bother with this article, more incorrect information than correct. \$\endgroup\$ – old_timer May 22 '17 at 17:11
  • \$\begingroup\$ dual core is a configurable option, not always there...(like the caches, the fpu, the mpu, etc, see the TRM). uses a full arm with thumb/thumb2 (armv7-ar) instruction set. vs the thumb/thumb2 you get with a cortex-m. just get the TRMs and ARMs and compare for yourself. \$\endgroup\$ – old_timer May 22 '17 at 17:19

Cortex-R series are used in pretty much industrial-specific applications such as DSP core fore automotive, digital cam, or SSD controllers. Because of the nature of industry world there is not much resource available other than ARM's TRM on internet yet. About thr development board, I found TI Herculus family has the cheepest development boards called BoosterPack ($20-$50). I believe Cortex M4 and Cortex M7 can do hard-realtime too though.

  • \$\begingroup\$ not sure what would make cortex-m4 and cortex-m7 special from the m3 or the m0 or m0+. Any of the cortex-ms will have a good interrupt response in that there are dozens to hundreds (chip and core implementation) of individual vectors vs the traditional one IRQ and one FIQ that software has to sort out. they should all do well the m4 and m7 have optional pseudo mmus and optional floating point which helps over their baby brothers. \$\endgroup\$ – old_timer May 22 '17 at 17:08
  • \$\begingroup\$ @old_timer Yes you're arguments are valid. I mentioned M4 and M7 because the 50-motor sounds like it might need DSP and FPU instructions. Otherwise the CPU cores themselves doesn't have much difference in terms of real-time responsiveness. But Cortex M0/+ are usually available for smaller package with less speedy clock. And the cost of MCUs don't have much difference in cost. So why not having M4 unless you have a specific MCU in mind or require ultra low power consumption. \$\endgroup\$ – Bumsik Kim May 22 '17 at 18:55
  • \$\begingroup\$ would have to make sure they get one with the fpu and other features as these are build time options. yes thats right the m4 and m7's I have have much higher cpu clock limits. \$\endgroup\$ – old_timer May 22 '17 at 19:16

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