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Running three BOOST-DRV8711 as "standalone" with one MSP430 Launchpad?

Other Parts Discussed in Thread: BOOST-DRV8711, MSP430G2553, DRV8711

Hi everybody. I've received BOOST-DRV8711 boards 2 weeks ago, plugged into my MSP-EXP430G2 LaunchPad (with the MSP430G2553 chip), connected a NEMA23 stepper, and following the User's Guide, loaded the firmware to MSP430, fired up the GUI, and... everything worked perfectly from the first run! Kudos to TI team, you did it again with a very affordable and simple to run Booster Pack, further enriching the Launchpad ecosystem!..

Now, as I've got 3 DRV8711 booster packs, I'm thinking about using them to replace the TB6560-based 4-axes driver board for my small CNC mill. Still pretty much a raw idea, so please anyone correct me if I'm wrong: though the documentations says this booster pack is not intended to be used as standalone, the primary function of the MSP430 Launchpad is to load the DRV8711's registers with correct values, and enable the motor's H-bridge by setting bit 0 of the 0x0 register to 1. Once that done the Launchpad could be safely "removed" and the motor drove by any appropriate signals on the STEP/AIN1 and DIR/AIN2 pins. Is this correct?

If the above correct, may I then use one MSP430 Launchpad to set the parameters to all three DRV8711 boards at once, then drive  them using X-Y-Z Step/Dir signals from my CNC controller (I'm using a DIY version of Planet-CNC board, http://www.planet-cnc.com/index.php?page=diy)? My idea is to develop a breakout board with the header to plug one MSP430 Launchpad and three DRV8711 booster packs into. The nSLEEP, RESET, as well as SPI of the DRV8711 boards are all connected together and to respective pins on the Launchpad, however the STEP and DIR pins of the DRV8711 board are not connected to Launchpad, but are broken-out to connect to respective X-Y-Z channels of the PlanetCNC board. Then the Launchpad would load and enable all the driver boards at once, which then will be driven by the PlanetCNC's Step/Dir signals, to control the mill... Would this work? Or I still need 3 separate SPI channels from 3 separate Launchpad to load the drivers' registries?

Any advise on this is very much appreciated. Thank you all in advance

Mac Ha

  • Hi Mac Ha,

    Glad to hear you had a good experience!

    I think I understand what you are trying to do. You want to configure the DRV8711 with the MSP430 then drive it with your CNC controller. I think this is doable, but you must ensure that VM power is not removed from the DRV8711. Once VM is removed the registers will reset.

    I would just make a giant breadboard and leave the LaunchPad and CNC driver connected.

    I would tie the nSLEEP and RESET lines together as you suggested. The single SPI peripheral on the MSP430 can then be muxed out to each DRV8711. You can select which DRV8711 SPI is active with the SCS pin and go through each one. You may be able to program all 3 at once, but I would not recommend this as you will not be able to read back on the SPI bus.

    Eventually I would recommend making your own 3 axis driver with a higher end MSP430 and 3 DRV8711 :)

    Let me know if you have any questions!

  • Thank you very much, Nick, for a quick response - that's what I've always liked about TI and this community!

    So, with your advice, I'll try - as the first test - just to put them all on the breadboard and mux directly one Launchpad to 3 DRV8711 boards. If this works OK, I'll start designing the breakout board for a more permanent solution. I think that I'll have to look deeper into the programming too, so on startup the MSP430 would automatically load some default parameters into the DRV8711 registries, having them ready to run. As I still have some spare MSP430 chips, eventually I may even free up the Launchpad for other projects... BTW, what did you mean with "higher end MSP430"?

    Kind regards,

    Mac Ha

  • "Higher end MSP430"

    If you are looking to design out the PIC :), a slightly higher end MSP430 could drive the multiple stepper drivers. Then you could have a single MSP430 sending the SPI signals and sending the drive commands.

    For sending the SPI signals the G2553 should be just fine.

  • Hi Mac Ha and TI Motor Application Team.

    I am too thinking along same line.

    It is great  booster-pack with enough flexibility.

    I wish TI will come forth with releasing the  source software (DRV8711 GUI) on public domain. 

    Mac Ha,

    Hopefuly TI will someday release them, until then please keep us posted about progress you make achieving your goal.

    Thanks for  sharing .

    Anthony