Forum Rule: Always post complete source code & details to reproduce any issue!
Results 1 to 9 of 9

Thread: Cnc Grbl 1.1f for T4 imxrt1062

  1. #1
    Junior Member
    Join Date
    Mar 2020
    Posts
    1

    Cnc Grbl 1.1f for T4 imxrt1062


  2. #2
    Senior Member
    Join Date
    Mar 2016
    Posts
    115
    I've been working with this (GRBL/HAL). It's going quite well and the few bugs are getting fixed quickly. GRBL/HAL is moving well beyond the limiting factors of the 8 bit Arduino world and making high end features like 4, 5 and 6 Axis milling available. The longer term plans for GRBL/HAL involve migrating even more high end CNC features into it.

    I have designed a breakout board/motion controller for it. It's still a bit early but my design is available here. Currently I have working boards on the bench and will be stress testing in a machine environment soon. When I've had a bit more testing, I will put the design under open source, make the board design available on OSHPark and provide gerbers. I'm excited about the T4.1 as that will allow avoiding the backside pins and make it easy for average system builders to use.

    Here are the basic design features:
    • 5 Axis controller.
    • External interfaces 5V minimum.
    • 3 Axis limit switch optoisolator interface.
    • Cycle/Start, Feed/Hold, Door and Halt support via an optoisolator interface.
    • Spindle on/off, PWM, direction and 0-10V interfaces.
    • Flood and Mist coolant relay drivers.
    • Vacuum/Dust Extraction relay driver slaved to Spindle on/off
    • 3 additional relay drivers.
    • Selectable relay voltage - 5 and 12V.
    • I2C interface (3.3V).
    • EEPROM (24LC SOIC footprint).
    • Screw Terminals for secure wiring.


    I've designed a number of GRBL breakout boards for various arduinos and, compared to them, the Teensy 4 is a joy to work with. I'm also doing GRBL/HAL boards for the Due' and MKRZERO - the clean T4 design puts them to shame.
    Last edited by PhilB; 03-01-2020 at 06:02 AM.

  3. #3
    Junior Member
    Join Date
    Nov 2019
    Posts
    3
    Nice work! Iím following your work on this. Looking to upgrade to 4 axis board for my machine.

  4. #4
    Senior Member
    Join Date
    Mar 2016
    Posts
    115
    Thanks. You might be interesting in the T4.1 version that I'm hoping to finish layout in the next couple of days. It will have 5 axes (with limits and enables), Ethernet and maybe USB Host (for MPG/Pendant). Not sure if support for the pendant will be ready soon but Ethernet in grblHAL should be fairly straightforward. It works on several other platforms using IwIP. I've also reworked the relay section to allow easy support of both direct coil drive of relays and TTL drive for SSRs and those ubiquitous Chinese relay boards. Plus, it will allow the slaved dust extractor to be run independently via a header (with a switch attached).

    Also, I'm considering getting a smallish number of boards built up. At least with the SMD components - sort of an unkit, the user would finish it with the TH components. Not sure what they would be priced at. guessing mid $20s.

  5. #5
    Junior Member
    Join Date
    Nov 2019
    Posts
    3
    Very interested in your T4.1 version. Your price point for an "unkit" would be amazing, even if it was a few more. I'll take 2 Currently running 2 different 3 axis GRBL machines (Carbide3D's Shapeoko XL, and Nomad 883, with an older Shapeoko 3 build in the works. ). I can't wait to test and have no problem soldering TH components.

    Embarrassing newb question, it looks like drivers are not part of the equation, so external drivers?

  6. #6
    Senior Member
    Join Date
    Mar 2016
    Posts
    115
    Yes, drivers are external.

    While integrated drivers are attractive for easy system building, they have some significant drawbacks: driver failure requires full board replacement, hard to match to specific CNC machine stepper needs, problematic heat management and mixing noisy high(er) voltage with 3.3V or 5V digital logic. And, to be honest, it's about design philosophy - fully integrated vs modular. In my mind, a CNC system is highly modular by nature. Higher end systems are all modular. In fact, I can only think of a couple fully integrated CNC motion controllers that support more than 1.2 Amp stepper drivers (i.e not RepRap machines). A solid mid range or higher CNC machine typically uses at least 4A controllers. The CNC forums I look at seem to have a strong bias toward modular systems.

    As to timing of an unkit, I have to get the T41E5XBB (T4.1 base, Ethernet, 5 AXIS Breakout Board) done and validated, then figure out pick and place, select a vendor and then run a batch. I'm sure there will be some hiccups along the way. It probably won't happen until July at the earliest.

  7. #7
    Junior Member
    Join Date
    Nov 2019
    Posts
    3
    Makes sense; I too have fallen victim to a failed onboard driver which required a replaced board. The GRBL board I'm using has intergraded DRV8818's and a giant heatsink that functions as the board mount as well. The board I'm using is a closed source Carbide3D GRBL board, but it's based on the Stepoko Sparkfun board.


    I also have limited work space on my table, so I need to figure that out to add a rotary table. Given a couple of months, I'm sure I'll figure something out. I'm totally appreciative of your endeavors, so a release anytime would be welcomed.
    Last edited by voltjap; 05-14-2020 at 05:07 PM.

  8. #8
    Junior Member
    Join Date
    Jun 2020
    Posts
    1
    Been able to run GRBL port on Bluepill STM32 @ ~240kHz step rate max with some tweaks.
    I wonder, how high T4 can go, considering more than 8 times MCU frequency?
    Probably interrupt latency will be a limiting factor, not the core frequency.

  9. #9
    Senior Member
    Join Date
    Mar 2016
    Posts
    115
    Why don't you ask the developer, Terje? He is quite responsive and helpful. Post your question in the issues section of the github repository. You can also read the code. He's done a great job of "HAL-ifying" GRBL, moving the processor dependent stuff into the driver section.

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •