<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 username_0 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](https://www.reddit.com/r/BIGTREETECH/comments/x8hyff/skr_mini_e3_v3_additional_tmc2208_5_stepper/) 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](https://github.com/MarlinFirmware/Marlin/blob/bugfix-2.1.x/Marlin/src/pins/stm32g0/pins_BTT_SKR_MINI_E3_V3_0.h) 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.  

---

