Author: AETEK

The changes shown here require knowledge in the field of Arduino IDE, Marlin and electrical engineering and can overwhelm normal users. Also, I would like to point out possible dangers that exist in certain interventions. All adjustments have been checked for function.

Difficulty: Advanced

What is this about?
The TMC2208 is a German development. I was made in Germany, too . This tutorial is about making the A5 quieter. It is not my intention to explain all possible options of the TMC2208. Like me, most users will buy these stepper drivers just for one reason: to have silence. I focus on installing and configuring these drivers.
Why use only two TMC2208?
The most noise comes from the Y-axis and the X-axis. Because the Z-axis rarely moves when printing you do not hear much noise. The TMC2208 can deliver less power than the standard A4988 driver. One Z-axis driver needs to power two motors at the same time. The avaliable motor current is divided between both motors.
You rarely hear the extruder motor. If you hear it, then at the retract. The extruder motor, however, requires a lot of torque to press the filament through the nozzle. Much torque means a lot of electric current. This is exactly what the TMC2208 can not do.
For these reasons I used the TMC2208 only for the X and Y axes.
The TMC2208 stepper driver includes the function of TL-Smoothers. So it does not make sense to install this extension when using the TMC2208.

→ I have written a separate article on how to reduce the noise of the extruder motor.

Note: 
If you opt for this optimization, then always do both the hardware, 
as well as the software conversion. 

Required Electrical Parts

• 2 x TMC2208 Stepper Driver Modules With Heatsinks
• Active Cooling Fan Solution^*
• Some cable and heat shrink

* Active Cooling Fan Solution
I recommend using active cooling for the MKS GEN_L mainboard. I have a 80mm 24V fan with an 3D-printed adapter from Thingiverse (only top part) connected directly to the power supply via a Zener diode. The motherboard fan is so quiet that I do not hear it. That's why it runs as long as the A5 is powered. I will not describe the cooling system in this manual. If questions arise I can be contacted via the forum.

Please first pull the A5 mains plug

Before you install the TMC2208 module into the MKS GEN_L motherboard you should remove the pin named “NC” for safety reasons. “NC” means “Not Connected”. I do not know if this contact is connected to the driver board. I have removed this “NC” pin therefore. So one experiences no unpleasant surprises.

If you Upgrade from the factory drivers (A4988) then leave the MS1, MS2 and MS3 jumpers (under the driver moduls) plugged in as it is.

When inserting the modules into the sockets, it must be noted that the mounting direction is different as with the A4988 driver (see photos).

Get the GND (minus) from the Power supply input (black wire).

Here is an online calculator for the TMC 2208 Stepper Drivers:
https://learn.watterott.com/silentstepstick/faq/

VREF 1.13v eq. 0.8A @ 45°C motor temperature.

VREF 1.13v eq. 0.8A @ 45°C motor temperature.

VREF 1.13v eq. 0.8A @ 45°C motor temperature.

This concludes work on the A5 hardware for this project. In order for the drivers to work, the Marlin firmware has to be adjusted.

In the Arduino IDE open the A5 Custom Community Firmware (see article here in WIKI).

The TMC2208 needs a reverse drive on the DIR signal like the A4988.
This can be adjusted in the firmware.
Otherwise the motors will run in the wrong direction.
Adjust the following option in the file “Configuration.h” (TMC2208 for X & Y Axis)
Invert the stepper direction
#define INVERT_X_DIR false
#define INVERT_Y_DIR true

The following adjustments are made in the “.h” file:

Search for: bla

Replace this original code block…

#define E0_AUTO_FAN_PIN -1

…with this customized code:

#define E0_AUTO_FAN_PIN 7  

Then upload the changed firmware to the A5 (instructions here in the WIKI).
The 3D printer can now be reassembled.

1. Insert mains plug.
2. Power on the printer

If everything reacts like that, then enjoy the silence.

This completes the conversion.

Status 6. July 2018: Under Construction….