Dynomotion

Group: DynoMotion Message: 11789 From: freya_pilot Date: 6/26/2015
Subject: Help with JP7 Step Dir

Hi,


I have set my kflop up as a step and direction system but am having trouble with the config.


I am using JP7 and my X axis is setup on pins 15 and 16 (step and dir).  Pin 25 is going to COMM on my Gecko driver (201).  


Attached are screen shots of my setup but I can't get the system to actually move the stepper motor.  


The config and flash page is basically setup as No Input, Step and Dir Output and Output Channel 0.  I'm also muxing the channel (I'm not 100% sure that's what I need) but here's my setup.


Any help would be appreciated and hopefully once I get this motor moving, I'll be able to do the rest myself.


Thanks,

Steve


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Group: DynoMotion Message: 11791 From: Tom Kerekes Date: 6/26/2015
Subject: Re: Help with JP7 Step Dir [3 Attachments]
Hi Steve,

I think Gecko G201 needs the Common tied to +5V not GND.  So try KFLOP JP7 Pin 24 instead.  You can look at the picture on the cover of the drive and see that common needs to be positive so current can flow through the LEDs.  KFLOP should be in Open Collector mode to sink the current to GND.

HTH
Regards
TK 

Group: DynoMotion Message: 11792 From: freya_pilot Date: 6/26/2015
Subject: Re: Help with JP7 Step Dir
Tom,

After looking more closely at the stepper driver, I see what you mean with the diagram, thanks for the help,  I now have the stepper moving oddly.  When I go to the Step/Response screen and click Step I get a single step, pause, then another heavier step. I got rid of the 0X40 in  the 

FPGA(STEP_PULSE_LENGTH_ADD)=32 + 0x40;

When I select Move I get nothing.  

I'm also not sure if it means much but when the plot is generated I get Command (single square wave), Position (nothing, but that's expected) and Output (nothing but I was expecting something here).

Am I missing something blatantly obvious or is there something else I don't know, (I know I opened that one up).

Thanks again,
Steve
 
Group: DynoMotion Message: 11801 From: Tom Kerekes Date: 6/27/2015
Subject: Re: Help with JP7 Step Dir
Hi Steve,

You may need 4us pulses for Geckos as shown in the SetStepPulseLengthGecko.c example and below.  The value of 32 will provide 2us pulses that may not be seen by the Gecko.

Reversing the polarity with 0x80 give more direction setup time and avoids a microstep in the wrong direction when the direction reverses (but that isn't your problem at this point).

    // Geckos work well with this and "open collector" outputs
    FPGA(STEP_PULSE_LENGTH_ADD) = 0x80 + 63; // set inverted and to max 4us
Use only the "Move" button (unlike servos, Step/Dir systems can't change the commanded position instantly).

HTH
Regards
TK