Aiph5u
May 23, 2024, 7:49pm
53
Hey Mike,
unfortunately, on the Onefinity Controller the motor enable lines from the internal stepper drivers are not laid to the outside. They are there but if you want to access them, even an experienced solderer will have difficulties to access them.
On the AVR mainboard, the AVR microcontroller controls the four Texas Instruments DRV8711 stepper drivers over the
step{X,Y,Z,A},
dir{X,Y,Z,A},
motor enable, and
motor fault inputs.
On the original Buildbotics controller, which evolved a bit further ([1] , [2] ), these control ports are accessible from the outside over a a 15-pin Auxiliary motor control port . This allows you to drive any external stepper driver, including closed-loop drivers. Unfortunately on the Onefinity hardware fork, you don’t have this 15-pin auxiliary port.
There was one user interested in using third-party servo drivers who reported having done that and used these external Closed-loop Stepper Drivers on the Buildbotics controller. For this, it was needed to modify the Buildbotics controller to lead the points mentioned above (step{X,Y,Z,A}, dir{X,Y,Z,A}, motor enable, fault) in the circuit out. A description of the project that user made can be found here . Finally the new Buildbotics Controller has the onboard connectors J1 and J2 on pcb / J1 and J2 on the schematics now which lead the circuit points out to the 15-pin auxiliary I/O port for connection of external stepper drivers.
You may ask, will this work with the Onefinity Controller, which is a hardware fork of the Buildbotics controller? Well the points in the circuit are there, at the inputs of the internal DRV8711 stepper drivers, however unlike on the Buildbotics, they are not led out. If you have the confidence to solder with an SMD soldering tip and to wire your own 15-pin auxiliary I/O port, like the user mentioned above did with the Buildbotics controller, then it would work. Note that the pcb layout of the Onefinity Controller (v4 (power rocker switch version) , v5 (power push-button, self-powering off version) ) differs from the Buildbotics controller’s pcb layout .