Updating my Firmware

In order to be able to run my extruder without it being at temperature, I need to upgrade to Repetier firmware v 0.92.

In order to do the upload, I need to know about the motherboard.

There is no information about the motherboard that I could find printed on the motherboard, or in any of the documentation I had.

Fortunately, I was able to find the motherboard for sale by itself, with the necessary specs listed.

Here's the link to the sale page.

In case the link goes away, here's the info I got from the link.

Tronxy X3A Motherboard Info

Name: Melzi 2.0 1284P 3D printer PCB Board

Model Number: Melzi

Processor: ATMEGA 1284P

Searching the web for ATMEGA 1284P shows that it is an 8-bit microprocessor with 128kB flash, 4KB EEPROM, 16KB SRAM.

So on the Repetier Firmware configuration, I choose Atmel 8-bit for the processor and Melzi board for the motherboard.

Printer type is Cartesian

EEPROM usage: EEPROM set 1

Z Length: 315

At this point, I have no distortion correction, so I won't enter anything.

Trying to Compile Marlin for X3A

Installed Arduino 1.8.2

Added Sanguino board (open preferences, add
https://raw.githubusercontent.com/Lauszus/Sanguino/master/package_lauszus_sanguino_index.json
to the Additional Boards Manager URL's entry.  Open Tools/Boards/Board Manager.  Go to Sanguino entry and select it.  Click on the Install button.)

Set Board to Sanguino

Set Processor to ATMEGA 1284, 8 MHZ

Got errors because the C code isn't compatible with 1.8.2

Installed Arduino 1.0.6 (which uninstalls 1.8.2)

Download the Sanguino files from https://github.com/Lauszus/Sanguino

Copied them to my sketch directory, in a hardware/ folder (as described in README.md).

Started up Arduino 1.0.6

Set board to Sanguino W/ATmega1284 8 MHz

Set Serial port to Com5 (which is the one that was added by my USB driver).

Got an error "speed_lookuptable_fast" was not declared in this scope.

Set board to Sanguino W/ATmega1284 16 MHz.

Successful compilation!  YAY!

Note to self -- I think that I might have gotten the code to work properly with Arduino 1.8.2 by changing the name of the type that gave the error (but I had the wrong processor).  Maybe I need to try 1.8.2 out again.

I was able to get the Marlin code working properly with Arduino 1.8.2.  To do so I need to change fpos_t to fpos_type in the source.

Compiling Repetier

I would like to be able to switch back and forth between repetier (for manual leveling) and marlin (for autoleveling).  So I need to make sure I can compile both.

Unfortunately, I couldn't get Repetier working with Arduino 1.8.2.  So I'm going to go back to 1.0.6.

Downloaded Arduino 1.0.6.

Need to download Sanguino board info (I had it on my PC, but not on my Mac).

Install it in the Sketchbook directory (which is found in Arduino preferences).

FIle compiles. 

OK.  Now I can do both the Marlin and the Repetier.  I guess it's time to try the firmware update.  

TO be able to check things, I added CDS to UI_PRINTER variables in Configuration.h.  That way I will see that I have made a difference.

connected to serial port.  Pressed the upload button.  Got the following error:

avrdude: stk500_getsync(): not in sync: resp=0x73

  Note: this was with the serial port tty.usbserial.

 Now I will try with cu.usbserial

Same error message.

It appears that the problem is the Melzi board doesn't have a bootloader.

So I have ordered the necessary devices to install a bootloader.

I ordered a USBasp, with a 10 to 6 pin converter.

https://www.amazon.com/gp/product/B014J2BMAG

https://www.amazon.com/gp/product/B00CW80MP6

I downloaded the USBasp driver using Zadig for Windows 10.

http://zadig.akeo.ie/

I started up Zadig.  I inserted the USBasp into one of my USB ports.  Zadig automatically detected the hardware configuration of the USBasp.  I selected the libusb-win32 driver and installed it.


I turned off the power to the printer.  I opened up the Tronxy controller box.  I removed the LCD panel cable from the Melzi board.I changed the jumper on the Melzi board to USB power from external power (it's hard to see because the print is so fine, but there's only one set of three jumper pins in a row).  I installed the 6 to 10 pin converter on the 6-pin header at the rear of the Melzi board.  The pin names are listed on the board and on the converter; make sure they match.   I connected the USBasp to the 10 pin side of the converter.  I connected the USB cable from the Tronxy to one of the USB ports on my computer. (So now I have two connections to the Melzi board: the USBasp and the USB cable).

I opened up Arduino (I used version 1.0.6 for this process).  I selected the Sanguino Atmega 1256 16 MHz board.  I selected the USBasp programmer.  I selected the appropriate COM port for my printer.

Then I clicked on the Burn Bootloader button, and waited for a couple of minutes.  After a couple of minutes, it told me the bootloader was downloaded successfully.

So then I opened my Tronxy Repetier firmware in Arduino.  I did a test compile, and everything worked.  I then clicked on the upload button.  It compiled, and took what seemed like an eternity, but it said the firmware was uploaded.

I disconnected the USBasp.  I reset the power jumper to external power.  I reconnected the LCD panel.  I turned on the power.  The printer booted successfully.  Unfortunately, however, the firmware I had loaded didn't have any changes from the factory firmware, so I didn't know if the change had worked.

So I opened a copy of the Tronxy Marlin firmware in Arduino.  I changed the name of the printer (it's in Configuration.h, CUSTOM_MENDEL_NAME).  Did a test compile, followed by an upload.  And the printer reset and had my new name!

It was really easy to update the firmware once I had a bootloader on the Melzi board.  If I can do it, you can too!

Uploading Firmware from my MacBook Pro

I wanted to do an upload on a new Tronxy X3A my son purchased.  My Windows 10 notebook wasn't working, so I decided to try it on my MacBook Pro.

I prepared the motherboard the same way:

1. Moved the power jumper to the bottom two pins (USB power)
2. Unplugged the LCD
3. Connected the 6-pin connector on the USBAsp to the six-pin header on the Melzi.  Make sure VCC goes to 5V and GND goes to GND.
4. Connected a USB cable between the MacBook and the USB B port on the Melzi
5. Plugged in the USBAsp to another USB port on the MacBook

I started up Arduino (I'm using 1.86).

Set the proper settings:

• Board: Sanguino
• Processor: ATMega 1284 16 MHz
• Programmer: USBAsp
• Port: /dev/cu.usbserial-A501S6NS  (it's the new one added when the USB cable is plugged into the Melzi board

Check the connection: 

• Tools: Board Info

Burn the bootloader:

• Tools:Burn Bootloader

Don't worry about the warning:

warning: cannot set sck period. please check for usbasp firmware update.

It's just a warning.

Unplug the USBAsp.

Open your Marlin firmware in Arduino, and Upload.  You should see an "Uploading" progress bar on the lower right of the window.  Wait what seems like forever until the upload is complete.

If you have problems uploading, it might be good to open the Arduino Preferences window and set the Show verbose output during upload checkbox.

Disconnect the USB cable

Reset the Power Jumper

Reconnect the LCD

Turn on the power.  You should now have the new Marlin.

Making a hex file to use Octoprint to upload new version of firmware

In Arduino, go to Sketch/Export Compiled Binary

This will create a .hex file that you can upload with Octoprint

Avoiding Z-Axis Desynchronization

One of the problems with the Tronxy printer is that the Z axis is driven by two independent stepper motors.  That means that if only one moves, the calibration of the Z axis is hosed, and it's back to synchronizing the Z axis and releveling the bed.  I'm getting faster, but it's still a pain in the neck.

The most common reason for losing synchronization in my experience is that the right-side motor shifts while I am messing with the filament (changing filament, adjusting the extruder, etc.).

The rule I have developed to avoid problems is this:

ALWAYS HAVE THE STEPPER MOTORS ENABLED WHEN TOUCHING THE EXTRUDER

With the steppers enabled, I have never had the Z-axis motor spin while adjusting the extruder.

 

Getting my parts centered on my print bed

One of the issues I've had is that my parts aren't where I want them to be on my print bed.  It's because I haven't had the bed set up properly.  So let me say how I fixed it.

On the Tronxy X3 the home position is off the print bed.  It's about 20 mm to the left of the bed, and about 40 mm in front of the bed.  But the home position is x=0, y=0 on the printer.

By default, Repetier-host sets up with the front left corner of the print bed at (0,0).  But as I just said, (0,0) on the printer isn't at the front left corner.

To fix this, do the following:

Find the X coordinates of the left and right sides of the print area

Turn on your printer.  Using the Buttons and the LCD panel, home all the axes.  Then, using the LCD panel Position/X Pos. Fast menu item, move the head until the extruder is at the left end of the desired printing area.  For me, that's a little to the right of the edge of the table.  Read the X position (in my case, 23.00 mm).

Then move to the right of the desired printing area.   In my case, 223.0 mm. Note that it's 200 mm greater than the left end, which is what I expect.

Find the Y coordinates of the front and back of the print area

Repeat the process for the Y axis (making sure the extruder nozzle clears the print bed).  For me, the front of the print area was 34.00 mm, and the back of the print area was at 230.0 mm (this appeared to be a hard limit set in the firmware, as the carriage hadn't hit a physical stop, and the nozzle wasn't at the back of the print area.  Later on, I'll try to adjust it in the firmware.)  So to keep the full 200 mm of travel in the Y direction, I will set the front of the print area to 30.0 mm.

Enter the settings into Repetier-host

Click on printer settings in Repetier-host.  Enter 0 for the X min and the Y min.  Enter the maximum numbers you found in the previous steps for X max and Y max (223 and 230 for me).  Set the width and depth of the print area to 200.  Set the Bed Front to the value obtained in the previous step (30 mm for me).  Set the Bed Left to the left side X value found above (23 mm for me). 

Now you're ready to go!  Make sure that slicer is set to 200 mm by 200 mm, with the origin at (0,0).  Make sure your STL files get placed in the center of the work area (use the Center Object button on the Object Placement panel if necessary).  Now you should have your objects right in the center of your bed.  And most importantly, the bed in the Object Placement panel accurately represents your printer bed.

Happy printing!

SD Card Info

It seems some people did not get a microSD with their printer (with me, it came in a USB-micro-SD convertor).

But if you're in that position, here's the files that came with mine.

Zip Archive