# Problems with UART connection with SKR Mini E3 V2 and BTT Pi V1.2

**URL:** <https://klipper.discourse.group/t/problems-with-uart-connection-with-skr-mini-e3-v2-and-btt-pi-v1-2/24300>\
**Category:** General Discussion\
**Created:** [July 20, 2025, 7:32pm UTC](https://klipper.discourse.group/t/problems-with-uart-connection-with-skr-mini-e3-v2-and-btt-pi-v1-2/24300 "2025-07-20T19:32:34Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Valjevac91](https://avatars.discourse-cdn.com/v4/letter/v/bc79bd/32.png) [@Valjevac91](https://klipper.discourse.group/u/Valjevac91)\
**Post date:** [July 20, 2025, 7:32pm UTC](https://klipper.discourse.group/t/problems-with-uart-connection-with-skr-mini-e3-v2-and-btt-pi-v1-2/24300/1 "2025-07-20T19:32:34Z")

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### Basic Information:

Printer Model: DIY Core XY  
 MCU / Printerboard: SKR Mini E3 V2  
 Host / SBC BTT PI V1.2  
 klippy.log  
[klippy (1).log](https://klipper.discourse.group/uploads/short-url/nQmAuRFkV9Ie8vogSFrXYho7dYe.log) (1.6 MB)

_Fill out above information and_ **_in all cases attach your_ `klippy.log` _file_** (use zip to compress it, if too big). _Pasting your_ `printer.cfg` _is **not** needed_  
_ **Be sure to check our “Knowledge Base” Category first. Most relevant items, e.g. error messages, are covered there** _

### Describe your issue:

After i finished building printer.cfg and trying to home my X and Y axis (Sensorless Homing) i got this ERROR from Klipper ‘Unable to read tmc uart ‘stepper\_y’ register IFCNT’, i tryed to find a solution everywhere but to no luck. I would really appreciate any help.  
I have Jumper on both X and Y axis for Sensorless homing on board, Z axis is with Endstop switches and it is working perfectly.  
…

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**Author:** ![mykepredko](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/mykepredko/32/2085_2.png) [@mykepredko](https://klipper.discourse.group/u/mykepredko)\
**Post date:** [July 20, 2025, 8:12pm UTC](https://klipper.discourse.group/t/problems-with-uart-connection-with-skr-mini-e3-v2-and-btt-pi-v1-2/24300/2 "2025-07-20T20:12:34Z")

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Where did you get the pin information for the TMC2209s on the board?

The failure is indicating that Klipper can’t communicate with the TMC2209s on the board via their serial port.

I just looked at your `klippy.log` and you have:

```kcfg
[tmc2209 stepper_x]
uart_pin = PA3
diag_pin = PC0
uart_address = 0
run_current = 0.580
hold_current = 0.500
stealthchop_threshold = 999999

[tmc2209 stepper_y]
uart_pin = PA2
diag_pin = PC1
uart_address = 2
run_current = 0.580
hold_current = 0.500
stealthchop_threshold = 999999

[tmc2209 stepper_z]
uart_pin = PC11
tx_pin = PC10
uart_address = 1
run_current = 0.580
hold_current = 0.500
stealthchop_threshold = 999999

```

You have different values for the `uart_pin` when it should be `TX4`/`PC10` for all of them.

I did a quick check of the specified EN/DIR/STEP pins and they look okay.

You should also add a `[TMC2209 extruder]` statement.

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**Author:** ![Valjevac91](https://avatars.discourse-cdn.com/v4/letter/v/bc79bd/32.png) [@Valjevac91](https://klipper.discourse.group/u/Valjevac91)\
**Post date:** [July 20, 2025, 8:22pm UTC](https://klipper.discourse.group/t/problems-with-uart-connection-with-skr-mini-e3-v2-and-btt-pi-v1-2/24300/3 "2025-07-20T20:22:23Z")

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Thank you for your fast reply, i will try it tomorrow with these changes, it is my first klipper build so i asked ChatGPT for some help, but it was not so much of a help, it made more problems and in the end, i ended here…😁

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**Author:** ![system](https://global.discourse-cdn.com/free1/uploads/klipper/original/1X/64419bf2aac6639e6ef5cef200dcd456b0a01ac3.png) [@system](https://klipper.discourse.group/u/system)\
**Post date:** [September 18, 2025, 8:23pm UTC](https://klipper.discourse.group/t/problems-with-uart-connection-with-skr-mini-e3-v2-and-btt-pi-v1-2/24300/4 "2025-09-18T20:23:05Z")

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