# Loss of connection to mcu

**URL:** <https://klipper.discourse.group/t/loss-of-connection-to-mcu/6440>\
**Category:** General Discussion\
**Created:** [February 5, 2023, 3:17pm UTC](https://klipper.discourse.group/t/loss-of-connection-to-mcu/6440 "2023-02-05T15:17:16Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Brandon.C](https://avatars.discourse-cdn.com/v4/letter/b/53a042/32.png) [@Brandon.C](https://klipper.discourse.group/u/Brandon.C)\
**Post date:** [February 5, 2023, 3:17pm UTC](https://klipper.discourse.group/t/loss-of-connection-to-mcu/6440/1 "2023-02-05T15:17:17Z")

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Printer Model: Ender 3  
 MCU / Printerboard:skr mini e3 v1.2 with raspberry pi 4  
 `klippy.log`  
[klippy.log (1).txt](https://klipper.discourse.group/uploads/short-url/1axR79L958fVefwst9Bbq9AKme7.txt) (6.2 MB)

Everytime when im printing so far, the printer loses connection to the mcu. I’ve change the usb and added a ferrite core to both the pi 4 power supply and to the usb. Tried the print again and it got further this time but still lost connection.  
I’m hoping someone can assist me with this as im at a loss.

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<div class="post-metadata">

**Author:** ![DaVinci10](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/davinci10/32/2828_2.png) [@DaVinci10](https://klipper.discourse.group/u/DaVinci10)\
**Post date:** [February 7, 2023, 1:59am UTC](https://klipper.discourse.group/t/loss-of-connection-to-mcu/6440/2 "2023-02-07T01:59:13Z")

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I See this error in the file…

Got EOF when reading from device  
Stats 11372.2: gcodein=0 mcu: mcu\_awake=0.028 mcu\_task\_avg=0.000032 mcu\_task\_stddev=0.000060 bytes\_write=23798013 bytes\_read=5866381 bytes\_retransmit=931 bytes\_invalid=0 send\_seq=491573 receive\_seq=491564 retransmit\_seq=491573 srtt=0.000 rttvar=0.000 rto=0.100 ready\_bytes=43 stalled\_bytes=386 freq=71996862 sd\_pos=10824700 heater\_bed: target=60 temp=60.1 pwm=0.000 raspberry\_pi: temp=49.2 mcu\_temp: temp=49.2 sysload=0.10 cputime=747.195 memavail=3636544 print\_time=11384.991 buffer\_time=2.114 print\_stall=0 extruder: target=215 temp=214.9 pwm=0.688

then a few moments later comes the following.

Timeout with MCU ‘mcu’ (eventtime=11376.182926)  
Transition to shutdown state: Lost communication with MCU ‘mcu’  
Dumping gcode input 0 blocks  
Dumping 20 requests for client 3041943720