<p>This is not that difficult, but you need some experience in configuring and compiling (Marlin) firmware.</p>
<p>In fact, you already linked to the solution. From the <a href="https://www.reddit.com/r/BIGTREETECH/comments/x8hyff/skr_mini_e3_v3_additional_tmc2208_5_stepper/" rel="nofollow noreferrer">link</a> you see that the person used the following pins to connect to the separate stepper driver on the breadboard:</p>
<div class="s-table-container"><table class="s-table">
<thead>
<tr>
<th>Wire</th>
<th>Description</th>
<th>SKR pin</th>
<th>Stepper pin</th>
</tr>
</thead>
<tbody>
<tr>
<td>GND</td>
<td>ground</td>
<td>PD4</td>
<td>DIR</td>
</tr>
<tr>
<td>Vio</td>
<td>3.3v on SPI1 header</td>
<td>PD5</td>
<td>STEP</td>
</tr>
<tr>
<td>OB2</td>
<td>to motor M2B</td>
<td>n/c</td>
<td>CLK</td>
</tr>
<tr>
<td>OB1</td>
<td>to motor M2A</td>
<td>either one</td>
<td>PDN_UART</td>
</tr>
<tr>
<td>OA1</td>
<td>to motor M1B</td>
<td>either one</td>
<td>PDN_UART</td>
</tr>
<tr>
<td>OA2</td>
<td>to motor M1A</td>
<td>n/c</td>
<td>MS2</td>
</tr>
<tr>
<td>GND</td>
<td>ground</td>
<td>n/c</td>
<td>MS1</td>
</tr>
<tr>
<td>Vm</td>
<td>to 24v from PS</td>
<td>PD0</td>
<td>ENN</td>
</tr>
</tbody>
</table></div>
<blockquote>
<p>In words, what you're seeing here is that I am taking 3.3v and ground from the SPI header, and taking the pins we need for STEP, DIR, ENN (enable), and the UART from the &quot;I/O&quot; connector. Add 24v power (and ground) from the power supply.</p>
<p>Now about the UART cable. You'd need to fashion a cable to go from one of the TMC2208's &quot;PDN_UART&quot; cable, split into two wires, one of which has a 1k resistor. The side without the resistor goes to PD2 and the one with the resistor goes to PD3.</p>
<p>Last thing, not shown but rather important: a 100uF electrolytic capacitor rated for 35v or higher. This will bridge the 24v and ground lines and should be close to the driver. I don't really need it for proof of concept but when driving actual loads during actual prints it's gonna be important.</p>
<p>I also had the idea of using the EXP1 connector's pins too. (As a klipper user, my e3v2's fancy screen don't work anyway.) Could fashion a single plug to hook up all the needed wires save for power. Wound up leaving that option open for the future.</p>
</blockquote>
<p>As you are altering the board (adding a stepper) I'd prefer to define the extra stepper in the <a href="https://github.com/MarlinFirmware/Marlin/blob/bugfix-2.1.x/Marlin/src/pins/stm32g0/pins_BTT_SKR_MINI_E3_V3_0.h" rel="nofollow noreferrer">SKR Mini E3 v3.0</a> pin specification file.</p>
<p>E.g. append the stepper section to read:</p>
<pre><code>//
// Steppers
//
#define X_ENABLE_PIN                        PB14
#define X_STEP_PIN                          PB13
#define X_DIR_PIN                           PB12

#define Y_ENABLE_PIN                        PB11
#define Y_STEP_PIN                          PB10
#define Y_DIR_PIN                           PB2

#define Z_ENABLE_PIN                        PB1
#define Z_STEP_PIN                          PB0
#define Z_DIR_PIN                           PC5

#define E0_ENABLE_PIN                       PD1
#define E0_STEP_PIN                         PB3
#define E0_DIR_PIN                          PB4

#define E1_ENABLE_PIN                       PD0
#define E1_STEP_PIN                         PD5
#define E1_DIR_PIN                          PD4
</code></pre>
<p>If UART is used be sure to set the <code>E1_HARDWARE_SERIAL</code> and the <code>E1_SLAVE_ADDRESS</code> in the section under the stepper section.</p>
<p>Furthermore, change the <code>config.h</code> to include you have multiple extruders:</p>
<pre><code>#define EXTRUDERS 2
</code></pre>
<p>I assume you don't use 2 heaters and 2 temperature probes, so set:</p>
<pre><code>#define SINGLENOZZLE 
</code></pre>
<p>And select a driver type:</p>
<pre><code>#define E1_DRIVER_TYPE TMC2208
</code></pre>
<p>For what it's worth, or depending on your hard- and software skills, you could probably better buy a new controller board with more stepper drivers; these boards are very affordable these days.</p>

CC BY-SA 4.0
2024-03-14T20:45:43.000Z
Thank you for the answer. I have got a problem now. I connected the BTT TFT35 E3 V3.0.1 to my printer. Every time i compile a Firmware and load it into the Printer the rotary knob doesn't work and the Screen wont connect with the printer. I have tried some ideas from other creators, but everything doesn't work.
David Kania Adri
CC BY-SA 4.0
2024-03-12T13:02:34.470Z
2024-03-12T13:02:34.470Z
0scar
<p>I am trying to add a second extruder motor to my Ender 3 V2 so I can use both independently.
My Ender 3 V2 has an SKR Mini E3 v3 build in.
I have seen the post <a href="https://www.reddit.com/r/BIGTREETECH/comments/x8hyff/skr_mini_e3_v3_additional_tmc2208_5_stepper/?sort=new" rel="nofollow noreferrer">SKR Mini E3 v3 + additional TMC2208 = 5 stepper drivers (works!)</a> and tried to build it. But now I am stuck building the Marlin firmware.</p>
<p>Has anybody done this before, or know how to do that?</p>

CC BY-SA 4.0
2024-03-04T18:29:24.777Z
Hi David and welcome! Please [edit] your question and post the errors (or output) *as text* (`code formatted text`) that you are encountering (not in this comment section). Without knowing what the errors are, it will be impossible to answer your question, unfortunately.
Greenonline
<creality-ender-3><marlin><stepper-driver><creality>
Add 5th stepper driver to the SKR mini E3 v3 to use it for a second extruder motor
David Kania Adri
# Add 5th stepper driver to the SKR mini E3 v3 to use it for a second extruder motor

(Asked by: username_0 on 2024-03-04)

I am trying to add a second extruder motor to my Ender 3 V2 so I can use both independently.
My Ender 3 V2 has an SKR Mini E3 v3 build in.
I have seen the post [SKR Mini E3 v3 + additional TMC2208 = 5 stepper drivers (works!)](https://www.reddit.com/r/BIGTREETECH/comments/x8hyff/skr_mini_e3_v3_additional_tmc2208_5_stepper/?sort=new) and tried to build it. But now I am stuck building the Marlin firmware.

Has anybody done this before, or know how to do that?

**Tags:** creality-ender-3, marlin, stepper-driver, creality
> **Comments:**
> **username_1**: Hi David and welcome! Please [edit] your question and post the errors (or output) *as text* (`code formatted text`) that you are encountering (not in this comment section). Without knowing what the errors are, it will be impossible to answer your question, unfortunately.  

---

## 1 answers

### Answer by username_2 on 2024-03-12. Score: 1

This is not that difficult, but you need some experience in configuring and compiling (Marlin) firmware.
In fact, you already linked to the solution. From the link you see that the person used the following pins to connect to the separate stepper driver on the breadboard:



Wire
Description
SKR pin
Stepper pin




GND
ground
PD4
DIR


Vio
3.3v on SPI1 header
PD5
STEP


OB2
to motor M2B
n/c
CLK


OB1
to motor M2A
either one
PDN_UART


OA1
to motor M1B
either one
PDN_UART


OA2
to motor M1A
n/c
MS2


GND
ground
n/c
MS1


Vm
to 24v from PS
PD0
ENN




In words, what you're seeing here is that I am taking 3.3v and ground from the SPI header, and taking the pins we need for STEP, DIR, ENN (enable), and the UART from the "I/O" connector. Add 24v power (and ground) from the power supply.
Now about the UART cable. You'd need to fashion a cable to go from one of the TMC2208's "PDN_UART" cable, split into two wires, one of which has a 1k resistor. The side without the resistor goes to PD2 and the one with the resistor goes to PD3.
Last thing, not shown but rather important: a 100uF electrolytic capacitor rated for 35v or higher. This will bridge the 24v and ground lines and should be close to the driver. I don't really need it for proof of concept but when driving actual loads during actual prints it's gonna be important.
I also had the idea of using the EXP1 connector's pins too. (As a klipper user, my e3v2's fancy screen don't work anyway.) Could fashion a single plug to hook up all the needed wires save for power. Wound up leaving that option open for the future.

As you are altering the board (adding a stepper) I'd prefer to define the extra stepper in the SKR Mini E3 v3.0 pin specification file.
E.g. append the stepper section to read:
//
// Steppers
//
#define X_ENABLE_PIN                        PB14
#define X_STEP_PIN                          PB13
#define X_DIR_PIN                           PB12

#define Y_ENABLE_PIN                        PB11
#define Y_STEP_PIN                          PB10
#define Y_DIR_PIN                           PB2

#define Z_ENABLE_PIN                        PB1
#define Z_STEP_PIN                          PB0
#define Z_DIR_PIN                           PC5

#define E0_ENABLE_PIN                       PD1
#define E0_STEP_PIN                         PB3
#define E0_DIR_PIN                          PB4

#define E1_ENABLE_PIN                       PD0
#define E1_STEP_PIN                         PD5
#define E1_DIR_PIN                          PD4

If UART is used be sure to set the E1_HARDWARE_SERIAL and the E1_SLAVE_ADDRESS in the section under the stepper section.
Furthermore, change the config.h to include you have multiple extruders:
#define EXTRUDERS 2

I assume you don't use 2 heaters and 2 temperature probes, so set:
#define SINGLENOZZLE 

And select a driver type:
#define E1_DRIVER_TYPE TMC2208

For what it's worth, or depending on your hard- and software skills, you could probably better buy a new controller board with more stepper drivers; these boards are very affordable these days.

> **Comments:**
> **username_0**: Thank you for the answer. I have got a problem now. I connected the BTT TFT35 E3 V3.0.1 to my printer. Every time i compile a Firmware and load it into the Printer the rotary knob doesn't work and the Screen wont connect with the printer. I have tried some ideas from other creators, but everything doesn't work.  

---

