Feature request for duplication of the steps control sequence to another pins

[a0s]

I have RAMPS-FD board with six channels - six stepper driver that i can control. This channels is X, Y, Z, E0-MOT, E1-MOT, E2-MOT. X, Y, Z to control for movement, and E0-MOT to control the extruder. Therefore i have two empty channels. I have Prusa i3 printer with two motors for Z-axis. My problem is that i need control two motors by one stepper driver (Polulu DRV8825). I don't want to connect motors sequentially or parallel, i think its bad idea in general. I want using E2-MOT channel for second stepper driver of Z axis. First and second of Z-axis's stepper drivers should working synchronously for prevent printer damage. I guess that the configuration might look like this https://github.com/orangeudav/aprinter/commit/6367faf05ecb25410c758b68a05ab851a94f2c2c (aprinter-rampsfd.cpp) And control code should looks like

template <typename ThisContext>
static void stepOn (ThisContext c)
{
    auto *s = Steppers::Object::self(c);
    s->debugAccess(c);
    Context::Pins::template set<typename ThisDef::StepPin>(c, true);            

    // If this axis have one, two etc PrinterMainSlaveAxisParams - call stepOn for all of them
}

template <typename ThisContext>
static void stepOff (ThisContext c)
{
    auto *s = Steppers::Object::self(c);
    s->debugAccess(c);
    Context::Pins::template set<typename ThisDef::StepPin>(c, false);

    // If this axis have one, two etc PrinterMainSlaveAxisParams - call stepOff for all of them
}

I do not know enough C++11 and templates to implement this :(

[ambrop72]

Thanks for the request, that'll be easy to implement.

[ambrop72]

In your slave axes proposal, why do you have a Name in PrinterMainSlaveAxisParams? For the axis itself that identifies the axis in G0/G1 etc., but in your case I don't see how it is useful.

[a0s]

Yes, name not need. I I'm not going to re-use these pins anywhere.

[ambrop72]

Should be all set. Here's how you use it:

PrinterMainAxisParams<
    ...
    PrinterMainNoMicroStepParams, // Don't forget the comma.
    MakeTypeList<
        PrinterMainSlaveStepperParams<
            DuePinA9, // DirPin
            DuePinA10, // StepPin
            DuePinA11, // EnablePin
            false // InvertDir
        >
    >
>

So, add this list of slave steppers to the axis. There's no need to change definitions of other axes since SlaveSteppersList defaults to EmptyTypeList.

[a0s]

Thank you for commit, it work great!

[a0s]

Hmm, for now (995d4b876ef11e6a2ed5ae987d110c980eed0d8a) i don't see PrinterMainSlaveStepperParams example and for my config

           ...
           AxisDriverService<
                At91Sam3xClockInterruptTimerService<At91Sam3xClockTC3, At91Sam3xClockCompA>, // StepperTimer
                TheAxisDriverPrecisionParams // PrecisionParams
            >,
            PrinterMainNoMicroStepParams,
            MakeTypeList<
                PrinterMainSlaveStepperParams<
                    DuePin47, // DirPin
                    DuePin32, // StepPin
                    DuePin45, // EnablePin
                    false // InvertDir
                >
            >
        >,
        PrinterMainAxisParams<
            'E', // Name
            DuePin28, // DirPin
            DuePin36, // StepPin
            ...

i got

./main/aprinter-rampsfd.cpp:422:17: error: type/value mismatch at argument 4 in template parameter list for 'template<class TDirPin, class TStepPin, class TEnablePin, class TInvertDir> struct APrinter::PrinterMainSlaveStepperParams'
                 >
                 ^
compilation terminated due to -Wfatal-errors.

[ambrop72]

You need to make some changes in your main file due to the introduction of the runtime configuration system. You probably noticed that but I forgot to update the wiki for the slave steppers thing.

The problem is the InvertDir parameter. You need to pass a boolean configuration option (declared with APRINTER_CONFIG_OPTION_BOOL), not a boolean value. See XInvertDir for example. You should name the option with a unique name (e.g. XSlave1InvertDir).