V3 PCB Jumpers under motor drivers

I know its been a while but I’ve finally got round to rebuilding the bust groundstation. I’ve got the new V3 PCBs but am having a bit of trouble setting them up. There are 3 jumpers under the motor drivers that I have no idea what they do. Looking at the PCB they pull MS1,2 or 3 to 5v. Any clues where they should be?

I’ve connected it all up but cant get GPredict to drive even though it is engaged. I’m stumped!

Hey, MS stands for microstep and the standard Pololu Stepstick has the following configuration:

MS1 MS2 MS3 Microstep Resolution
Low Low Low Full step
High Low Low Half step
Low High Low Quarter step
High High Low Eighth step
High High High Sixteenth step

I haven’t checked yet if the standard configuration for the firmware has microstepping activated, since I’m currently at the mechanical build. But expect it to run in full step mode (i.e. one pulse from the arduino equals one 1.8° step of the motor).

Hi @g7kse, the MSx pins on the stepper motor drivers setup the amount of micro-stepping. Currently, the rotator-controller Arduino code implicitly assumes that all 3 of these pins are LOW. This would then be an open jumper on the PCB – the driver chip has internal pull-down resistors.

You can connect to the pro-mini with a PC and serial terminal directly. It is using a baud rate of 19200. Upon power-up, the board should start turning until it triggers the end stop switches to find Home, indicating the code is starting up ok.

You can bypass the homing function by commenting-out line 61 of the current code https://github.com/satnogs/satnogs-rotator-controller/blob/master/firmware/stepper_motor_controller/stepper_motor_controller.ino
Then sending either a “!” character or the string “AZ EL” and should have the controller respond with it’s notion of its current position.

… and thanks @Highcooley for responding also!

Great. Thanks for the info. It wont be long before we’re back up and running.

Alex, g7kse