Today we're gonna talk about how to install an A4988 and a DRV8825 on the
BigTreeTech SKR version 1.4 now a couple of things you might want to
consider this is how the board comes default with its jumpers so what I'm
gonna do is I'm going to show you how to set the jumpers correctly for this board
so I'm going to pop off these jumpers
you
now the current configuration that they actually have for these jumpers are for
UART type connections in the role that they're in so as you can see right
below it's read below that's not the configuration that this is actually
gonna be but we actually need to move the jumpers to the second row so it's
gonna be half red and half black and I'm placing these on MS0 set of pins MS1
set of pins MS2 set of pins and then the RESET pin according to the
directions now the directions can be found on
BigTreeTech github website I'll leave a link in the description so
you can find those but that's the first set of pins
now let's do the other set real quick here
you
and we're going to do MS0
MS1
MS2 and then RESET
talk about the A4988 in just a second we have cooling fins that we're gonna
place on top of here this will allow it to cool the actual chip down while it's
stepping now I also recommend but you don't need in this case a cooling fan
and there are four different cooling fans on the board you have this one here
and this one here which are direct power this one is actually controllable so
we're going to skip this one for now and this one may not be controllable I'm not
sure at the moment but what I'm gonna first show you how to do is place these
on here real quick so what you're going to do is you're
going to peel off the sticker and you're going to place
the cooling fins on top of the board so it's gonna be placed right over the
chip which is this dark patch in the center
and we're gonna do the same for this board this one I already have the
sticker off so I'm just gonna stick it on
and that'll wick away the heat that's generated
here's a close-up of the A4988 and I'm gonna point out one
or two things that will be obvious to a little bit later in the video first of
all we have our trim pod right over here this is used to adjust the calibration
of current running through your stepper driver initially they're probably
calibrated pretty good so you may not need to change them but the other things
I want to point out on the board so you can actually plug these in is the enable
pin over here
have a direction pin and a ground pin this way we can connect it correctly
without causing any damage on the DRV8825 we have a couple of
things that I need to point out on the board obviously we have our cooling fins
which now you know where they're placed but we also have our trim pod right here
this can be used to adjust the current on your board so that you can dial it in
to the correct calibration on the underside of the DRV8825
you can see that the enable pin being EN over here
is our enable pin now keep in mind that's how we're gonna use it to connect
it to our board so we're gonna line up that pin on the other side we do have in
the upper right hand corner the direction pin that you can see over here
that's also a great way to figure out where you're going to connect as well as
the ground pin right over here this is the underside of the SKR version 1.4 and
one thing I need to point out here is when we're looking for the enable pin
you can see it right here right next to the diag pins above the same goes for
the other ones that are right here here
here in here okay now that we know where to
connect these based on the enable pin
and we know that the enable pin from the previous portion just before this the
enable pin is located here here here here and here on the board we know how
to align them but you always want to double check so I usually pick this up
and I'll rotate it over I'll find the enable pin which is right
over here which means that I'm gonna turn it over like the so I'm going to
align it over the board and then I'm gonna apply a little bit of thumb
pressure to place it in correctly how the same thing goes for this but let's keep
in mind that when we rotate this over we're
gonna check to make sure we're the enable pin is which is right here so I'm
going to rotate that over and I'm going to install it like so
so the next thing I want to show you real quick is I want to install two
steppers so I'm going to take
this stepper and I'm going to connect it like so
the X stepper port for the NEMA 17 stepper motor
then I'm gonna do the same
other NEMA stepper motor I'm gonna place it in this port for the y-axis to
program the SKR version 1.4 we need to connect the USB serial cable so I'm
going to place the big side of the connector in here and then I'm going to
take the small side of the connector and connect it to the computer and you may
hear a beep
okay to start with as you can see we have the default firmware from the last
load that occurred on the board I want to show you this so you can note the
time and date so I'm gonna go over the manual real quick just so you can see
how the jumpers are supposed to be aligned over here we have the jumpers
and notice how there's three sets of pins and the two sets that we have
jumped are like so so next thing I'm going to do is I'm
going to open up VScode
now VScode has a plugin called PlatformIO that has been loaded on this if you
haven't seen it loaded you can check out the initial basics video
so what I'm gonna do now is I'm gonna go to the Marlin folder
then the source folder then the core folder then boards dot H inside boards H
I'm gonna do a search on SKR and what you have right here is board
underscore bigtree underscore SKR underscore V1 underscore four we're gonna
copy that
then we're gonna close out of board.h and we're gonna go and minimize
these two folders and go to configuration dot H what I'm going to do
is I'm going to search on motherboard
and I'm gonna highlight board underscore ramps underscore one four underscore EFB
I'm going to paste what we just copied and then I'm gonna scroll up and I'm
gonna change the serial port from 0 negative 1
and then I'm going to do a search on the
A4988 and as you can see down here these are
our steppers now if you noticed before each one of these there's a hash mark
that will comment out the line meaning that it can't be used in order to enable
it we need to remove the comment by backspacing so we're going to do it for
the X driver the Y driver the Zed driver and for
good practice we're gonna do E0 now they're all enabled for the
A4988 now we're not using two of them which doesn't really
matter but we are using the X and the Y now the A4988 does one sixteenth of a
step whereas the DRV8825 does one thirty-second of a step so what we need
to do in order to change it is copy the DRV8825 and paste it over the A4988
in the x driver type what we're gonna paste it here then
the next thing that we need to do is we need to scroll down and we need to check
something here now currently as you can see right here we have
stepper units that they've decided on being 80 steps 80 steps and then we'll
say 4,000 and 500 for X Y Zed and E0 being your first extruder now know you
can do many more extruders but we'll talk about that and another video but I
want to show you these are actual defaults that they assume you'll use for
these numbers but if we go over to like our web browser
and we do a search on reprap
calculator
and we go to let's say this link which apparently is disabled
and no longer works so we'll go to the Prusa one
and as you can see down here they have computations for how much filament were
not interested in that we are interested in the stepper motors
now these current stepper motors that were using have a degree of step of 1.8
degrees which means that it gives you 200 steps in a circle
that case that's what these NEMA 17 steppers are but our stepper drivers may
vary so in this case the driver microstepping
is 1/16 this is what the default A4988 looks like but if we have like 1/32
of a step for a different separate board like the DRV8825 will click here so the
default value that you get that you can use inside your stepper configuration
would be more like this for 400 so we know that for 1/32 for 1/16 of a step
it's probably gonna be 200 but in the case that I'm showing you I'm just
showing you from the example Marlin file so keep that in mind and there are other
variables in the equation such as belt presets there are different types of
belts that you can use so these will vary and then there's a pitch inside the
belt so keep all these things in mind also your pulleys but we're gonna go
back to VScode and we're gonna use the values that we were given so we have 80
for our X we're going to use that for the A4988 and for the
DRV8825 we're going to use 160 so the next thing that you want to do is
set up your compilation is you have to go to platformio.ini and right now
the default environment is set to megaatmega2560 this is not our chipset our
chipset is the LPC1768 according to the manual so we're gonna highlight that in
type LPC1768
next what we're going to do is we're going to go to the upload button down
here and this will compile or build and then upload our built software to our TF
drive or SD card on our board now I'm going to do that right now
this may take a few moments
now that compilation has finished we have a firmware.bin for our binary file so
what I'm going to do to load this is to remove the USB power
and then reconnect the USB power but before I do that I want to confirm that
the build actually occurred so I'm gonna go to VScode as you can see it said
that it took three minutes to compile but let's scroll up and look so for our
chipset being the LPC1768 it says successful so we know that it says that
the bill took place successfully so what we're gonna do is we're gonna go back to
the USB drive I'm gonna remove the power for USB
now I'm going to reconnect it
and note that the date and time have updated
okay off-camera connected the power supply with no power
on the system so there's nothing plugged in and the USB is not connected to the
system now if you've noticed right here I put
red marks on any place where there is positive our according to the schematic
now keep in mind I'll explain later about the E0 and E1 steppers (extruders) for
now we're gonna skip that and put the heat bed as well but for here I have 12
volts connected and a ground so what I'm gonna do now is I'm going to energize
the board but the first thing I'm going to plug in is I'm gonna plug in the USB
for the big side which I already have connected to my computer so I'm gonna
plug that in then I'm gonna plug in the other side again and you may hear beep
now I've done something wrong so I'm going to power this down and remove this
over here you need to move the plug to the 12-volt power
jumper setting so this is going to run off your power supply now now I'm going
to reconnect this
and I'm going to reconnect the USB to the computer
you don't hear a beep obviously because it's not running on USB power at the
moment now I'm going to plug this into the wall
now as you can see the board is now energized so do not touch it because
you'll damage one the board and also I'm concerned that you might hurt yourself
so do not touch the board as we already know the firmware is updated so I'm
going to go over to our desktop now my computer I've downloaded Printrun I'm
going to open this up I'm going to go to Pronterface
Pronterface I'm going to click a connect and as you can see over here it said
connecting now it says printer is now online so what I'm going to do is I'm
going to move the X stepper a hundred steps
now I'm going to move the wise stepper a hundred steps
so if you like my tutorial please press the like button and subscribe and thank
you for your time