# PIN Name not accepted by MCU **URL:** \ **Category:** General Discussion\ **Created:** [October 18, 2024, 8:42pm UTC](https://klipper.discourse.group/t/pin-name-not-accepted-by-mcu/19481 "2024-10-18T20:42:51Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Stucarius](https://avatars.discourse-cdn.com/v4/letter/s/6bbea6/32.png) [@Stucarius](https://klipper.discourse.group/u/Stucarius)\ **Post date:** [October 18, 2024, 8:42pm UTC](https://klipper.discourse.group/t/pin-name-not-accepted-by-mcu/19481/1 "2024-10-18T20:42:51Z")
### Basic Information: Printer Model: Voron 2.4 r2 MCU / Printerboard: BTT Pi2/CB2 and Kraken Host / SBC klippy.log [klippy.log](https://klipper.discourse.group/uploads/short-url/kewwESF8pR2AP4VcSQdH2SsRcRF.log) (246.9 KB) I am getting errors in Klipper saying: Pin ‘PD6’ is not a valid pin name on mcu ‘mcu’ I have even tried other pin addresses for blank parts of the board but I get the same error over and over. Any Ideas for whats going on? It has my build at a grinding halt. Also if you do not mind answer this for me. If I am able to pull the serial number for my controller (Kraken) then I did successfully flash its firmware right? Thanks, STUCARIUS ### Describe your issue: … ---
**Author:** ![Stucarius](https://avatars.discourse-cdn.com/v4/letter/s/6bbea6/32.png) [@Stucarius](https://klipper.discourse.group/u/Stucarius)\ **Post date:** [October 18, 2024, 8:45pm UTC](https://klipper.discourse.group/t/pin-name-not-accepted-by-mcu/19481/2 "2024-10-18T20:45:17Z")
Just adding that the addresses I am using (PD6) is right off the pin diagram for the Kraken. It is the CS pin for one of the motors and the documentation says this is the pin I should use for this motor. ---
**Author:** ![EddyMI3D](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/eddymi3d/32/1981_2.png) [@EddyMI3D](https://klipper.discourse.group/u/EddyMI3D)\ **Post date:** [October 19, 2024, 3:14am UTC](https://klipper.discourse.group/t/pin-name-not-accepted-by-mcu/19481/3 "2024-10-19T03:14:21Z")
Hello @Stucarius ! I do not find the error you mention in the log. The only one I find is this: ```auto mcu 'mcu': Unable to open serial port: [Errno 2] could not open port /dev/serial/by-id/usb-Klipper_Klipper_firmware_12345-if00: [Errno 2] No such file or directory: '/dev/serial/by-id/usb-Klipper_Klipper_firmware_12345-if00' ``` ---
**Author:** ![Stucarius](https://avatars.discourse-cdn.com/v4/letter/s/6bbea6/32.png) [@Stucarius](https://klipper.discourse.group/u/Stucarius)\ **Post date:** [October 21, 2024, 5:43pm UTC](https://klipper.discourse.group/t/pin-name-not-accepted-by-mcu/19481/4 "2024-10-21T17:43:33Z")
I don’t know why its not in the log. It is the error when ever I restart Klipper. I cannot change it to any other pin. It just errors on that pin number. Im starting to think its a problem with the mcu. The MCU is a BTT Kraken ---
**Author:** ![EddyMI3D](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/eddymi3d/32/1981_2.png) [@EddyMI3D](https://klipper.discourse.group/u/EddyMI3D)\ **Post date:** [October 21, 2024, 5:58pm UTC](https://klipper.discourse.group/t/pin-name-not-accepted-by-mcu/19481/5 "2024-10-21T17:58:16Z")
> [@Stucarius](#): > > I don’t know why its not in the log. Your first post was on Oct. 15th, the log is from October 3rd: ```auto =============== Log rollover at Thu Oct 3 12:02:26 2024 =============== ``` ---
**Author:** ![Stucarius](https://avatars.discourse-cdn.com/v4/letter/s/6bbea6/32.png) [@Stucarius](https://klipper.discourse.group/u/Stucarius)\ **Post date:** [October 21, 2024, 10:06pm UTC](https://klipper.discourse.group/t/pin-name-not-accepted-by-mcu/19481/6 "2024-10-21T22:06:45Z")
I’m not sure how that happened. Here is a Oct 21 roll over log. I checked it this time. [klippy (2).log](https://klipper.discourse.group/uploads/short-url/28SeXkA76qAXUytjBRguZpe7dad.log) (171.9 KB) ---
**Author:** ![Sineos](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/sineos/32/18_2.png) [@Sineos](https://klipper.discourse.group/u/Sineos)\ **Post date:** [October 22, 2024, 5:27am UTC](https://klipper.discourse.group/t/pin-name-not-accepted-by-mcu/19481/7 "2024-10-22T05:27:40Z")
Check the MCU on your board if it really is what you are expecting and provide your printer.cfg please ---
**Author:** ![Stucarius](https://avatars.discourse-cdn.com/v4/letter/s/6bbea6/32.png) [@Stucarius](https://klipper.discourse.group/u/Stucarius)\ **Post date:** [October 23, 2024, 3:45pm UTC](https://klipper.discourse.group/t/pin-name-not-accepted-by-mcu/19481/8 "2024-10-23T15:45:23Z")
The MCU is the stem32 and what should be there. I pulled the MCU and I am replacing it with another Kraken. I noticed the 3.3v light is not on. Perhapse the board is damaged. I should know pretty soon but I think the Klipper error is something else. ---
**Author:** ![Stucarius](https://avatars.discourse-cdn.com/v4/letter/s/6bbea6/32.png) [@Stucarius](https://klipper.discourse.group/u/Stucarius)\ **Post date:** [October 23, 2024, 9:20pm UTC](https://klipper.discourse.group/t/pin-name-not-accepted-by-mcu/19481/9 "2024-10-23T21:20:26Z")
Here is the config. I am get the error mcu ‘mcu’: Unable to connect. I put a new kraken in and everything went fine but I got this error [config-20241023-161742.zip](https://klipper.discourse.group/uploads/short-url/3DJHW18S1ZDhQV4FkCl4NbCOXO9.zip) (8.8 KB) ---
**Author:** ![Stucarius](https://avatars.discourse-cdn.com/v4/letter/s/6bbea6/32.png) [@Stucarius](https://klipper.discourse.group/u/Stucarius)\ **Post date:** [October 23, 2024, 9:26pm UTC](https://klipper.discourse.group/t/pin-name-not-accepted-by-mcu/19481/10 "2024-10-23T21:26:36Z")
I corrected the MCU ID from what is in the file. It should read: serial: /dev/serial/by-id/usb-Klipper\_\_stm32h723xx\_\_1D000F001251323532393433-if00 ---
**Author:** ![EddyMI3D](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/eddymi3d/32/1981_2.png) [@EddyMI3D](https://klipper.discourse.group/u/EddyMI3D)\ **Post date:** [October 24, 2024, 5:59am UTC](https://klipper.discourse.group/t/pin-name-not-accepted-by-mcu/19481/11 "2024-10-24T05:59:11Z")
So it works now? ---
**Author:** ![Stucarius](https://avatars.discourse-cdn.com/v4/letter/s/6bbea6/32.png) [@Stucarius](https://klipper.discourse.group/u/Stucarius)\ **Post date:** [October 24, 2024, 8:29pm UTC](https://klipper.discourse.group/t/pin-name-not-accepted-by-mcu/19481/12 "2024-10-24T20:29:23Z")
No. It is getting hung up on cannot communicate wit the MCU. I did the DFU update to the Kraken. Do I also have to boot the Kraken with a firmware SD in the slot? I didn’t think so but this is my first time with this board. ---
**Author:** ![EddyMI3D](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/eddymi3d/32/1981_2.png) [@EddyMI3D](https://klipper.discourse.group/u/EddyMI3D)\ **Post date:** [October 24, 2024, 8:32pm UTC](https://klipper.discourse.group/t/pin-name-not-accepted-by-mcu/19481/13 "2024-10-24T20:32:59Z")
> [@Stucarius](#): > > Do I also have to boot the Kraken with a firmware SD in the slot? Yes. The Kraken needs its own firmware compilation. ---
**Author:** ![Stucarius](https://avatars.discourse-cdn.com/v4/letter/s/6bbea6/32.png) [@Stucarius](https://klipper.discourse.group/u/Stucarius)\ **Post date:** [October 24, 2024, 9:52pm UTC](https://klipper.discourse.group/t/pin-name-not-accepted-by-mcu/19481/14 "2024-10-24T21:52:40Z")
I did it and it flashed correctly but the MCU will still n ot connect. I am at a loss for whats wrong ---
**Author:** ![EddyMI3D](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/eddymi3d/32/1981_2.png) [@EddyMI3D](https://klipper.discourse.group/u/EddyMI3D)\ **Post date:** [October 25, 2024, 6:20am UTC](https://klipper.discourse.group/t/pin-name-not-accepted-by-mcu/19481/15 "2024-10-25T06:20:13Z")
Please attach a new klippy.log file to your next post. ---
**Author:** ![Stucarius](https://avatars.discourse-cdn.com/v4/letter/s/6bbea6/32.png) [@Stucarius](https://klipper.discourse.group/u/Stucarius)\ **Post date:** [October 25, 2024, 2:54pm UTC](https://klipper.discourse.group/t/pin-name-not-accepted-by-mcu/19481/16 "2024-10-25T14:54:51Z")
Here is the klippy log [klippy (4).log](https://klipper.discourse.group/uploads/short-url/dPbQpzNVnHENSgQoB0D1tSh3yC.log) (47.9 KB) ---
**Author:** ![Stucarius](https://avatars.discourse-cdn.com/v4/letter/s/6bbea6/32.png) [@Stucarius](https://klipper.discourse.group/u/Stucarius)\ **Post date:** [October 25, 2024, 3:07pm UTC](https://klipper.discourse.group/t/pin-name-not-accepted-by-mcu/19481/17 "2024-10-25T15:07:55Z")
If I disconnect the Kraken and run a xxx/by-id/xxx I get this return: **usb-Klipper\_rp2040\_eddy-if00** **usb-Klipper\_stm32f042x6\_020032000443304353373720-if00** If I reconnect the Kraken I get this return" **usb-Klipper\_rp2040\_eddy-if00** **usb-Klipper\_stm32f042x6\_020032000443304353373720-if00** **usb-Klipper\_stm32h723xx\_1D000F001251323532393433-if00** So the Pi is communicating with the MCU. So what am I missing? ---
**Author:** ![Sineos](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/sineos/32/18_2.png) [@Sineos](https://klipper.discourse.group/u/Sineos)\ **Post date:** [October 25, 2024, 3:15pm UTC](https://klipper.discourse.group/t/pin-name-not-accepted-by-mcu/19481/18 "2024-10-25T15:15:48Z")
From your log: ```auto [mcu] serial = /dev/serial/by-id/usb-Klipper_Klipper_firmware_12345-if00 restart_method = command ``` and this is the only MCU definition you have in your whole config. I’m not sure what you are expecting. > [@Stucarius](#): > > **usb-Klipper\_rp2040\_eddy-if00** > **usb-Klipper\_stm32f042x6\_020032000443304353373720-if00** > **usb-Klipper\_stm32h723xx\_1D000F001251323532393433-if00** From this, it seems you have 3 different MCUs. It might make sense to also define them in your config with the `[mcu]` setting being your “main” board, so probably the Kraken. > [@Stucarius](#): > > So the Pi is communicating with the MCU. So what am I missing? This is a wrong interpretation. The above output just means that the board is enumerated as USB device in Linux. It does not mean that the correct firmware is correctly flashed and working in Klipper. It is a good start, though. ---
**Author:** ![Stucarius](https://avatars.discourse-cdn.com/v4/letter/s/6bbea6/32.png) [@Stucarius](https://klipper.discourse.group/u/Stucarius)\ **Post date:** [October 25, 2024, 3:47pm UTC](https://klipper.discourse.group/t/pin-name-not-accepted-by-mcu/19481/19 "2024-10-25T15:47:54Z")
The “Eddy” Is the BTT Eddy sensor That is part of the build. I thought the second ID was the BTT Pi2 and the third is the Kraken. Is that not correct? When I flashed the firmware on the MCU it did so successfully. I got the indicator light and the file name was changed to firmware.cu like it is supposed to do if it flashed correctly. I also flashed it via DFU just to be sure. I feel like there is something in the config file that I am missing which points klipper to the MCU. BTW when I say MCU I mean the Kraken Controller When I say Pi I mean the BTT Pi2. The use of motherboard seems to be fast and loose on the directions and forums. The Pi is the primary with the controller (MCU) as the secondary. Thus the Pi is the “Motherboard” That’s how we computer people see it. Perhapse the RepRap builder crowd is different? ---
**Author:** ![Stucarius](https://avatars.discourse-cdn.com/v4/letter/s/6bbea6/32.png) [@Stucarius](https://klipper.discourse.group/u/Stucarius)\ **Post date:** [October 25, 2024, 3:57pm UTC](https://klipper.discourse.group/t/pin-name-not-accepted-by-mcu/19481/20 "2024-10-25T15:57:47Z")
Should the Kraken be listed as “Kraken” or with its actual serial number under the MCU listing in the "generic-bigtreetech-kraken-cfg? [Next page](https://klipper.discourse.group/t/pin-name-not-accepted-by-mcu/19481.md?page=2)