# Pin 'ar44' is not a valid pin name on mcu 'mcu'

**URL:** <https://klipper.discourse.group/t/pin-ar44-is-not-a-valid-pin-name-on-mcu-mcu/10176>\
**Category:** General Discussion\
**Created:** [August 29, 2023, 10:01am UTC](https://klipper.discourse.group/t/pin-ar44-is-not-a-valid-pin-name-on-mcu-mcu/10176 "2023-08-29T10:01:11Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![capocchione](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/capocchione/32/6951_2.png) [@capocchione](https://klipper.discourse.group/u/capocchione)\
**Post date:** [August 29, 2023, 10:01am UTC](https://klipper.discourse.group/t/pin-ar44-is-not-a-valid-pin-name-on-mcu-mcu/10176/1 "2023-08-29T10:01:11Z")

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### Basic Information:

Printer Model: Anycubic Mega-S stock  
 Connected to Raspberry pi 3 with fluidd

### Describe your issue:

As title says, I’m still trying to connect an Anycubic Mega-S to a raspberry pi 3b+ with Klipper firmware and Fluidd.

Everything is set up (I think) but fluidd gives me the error in the title.

Here it is my printer.cfg file:

> <https://pastebin.com/bvFU08Jd>

This is the Klipper log:

> <https://pastebin.com/iVxh7kmc>

the mcu serial is correctly set with its unique id using

> ls /dev/serial/by-id/\*

Any help? Thanks!

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<div class="post-metadata">

**Author:** ![LifeOfBrian](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/lifeofbrian/32/2380_2.png) [@LifeOfBrian](https://klipper.discourse.group/u/LifeOfBrian)\
**Post date:** [August 29, 2023, 11:22am UTC](https://klipper.discourse.group/t/pin-ar44-is-not-a-valid-pin-name-on-mcu-mcu/10176/2 "2023-08-29T11:22:08Z")

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You can directly drag and drop your config files and klippy.log into your posts here without using an external file hoster.

Where is your config from?  
Depending on the used MCU/board there might be different pin aliases.  
Did you check what board is installed?

Maybe you have to put this underneath the serial entry inside the [MCU] category:  
`pin_map: arduino`

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<div class="post-metadata">

**Author:** ![capocchione](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/capocchione/32/6951_2.png) [@capocchione](https://klipper.discourse.group/u/capocchione)\
**Post date:** [August 29, 2023, 11:33am UTC](https://klipper.discourse.group/t/pin-ar44-is-not-a-valid-pin-name-on-mcu-mcu/10176/3 "2023-08-29T11:33:19Z")

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I’ve solved the issue putting this in the printer config:

> [board\_pins arduino-mega]  
> aliases:  
> ar0=PE0, ar1=PE1, ar2=PE4, ar3=PE5, ar4=PG5,  
> ar5=PE3, ar6=PH3, ar7=PH4, ar8=PH5, ar9=PH6,  
> ar10=PB4, ar11=PB5, ar12=PB6, ar13=PB7, ar14=PJ1,  
> ar15=PJ0, ar16=PH1, ar17=PH0, ar18=PD3, ar19=PD2,  
> ar20=PD1, ar21=PD0, ar22=PA0, ar23=PA1, ar24=PA2,  
> ar25=PA3, ar26=PA4, ar27=PA5, ar28=PA6, ar29=PA7,  
> ar30=PC7, ar31=PC6, ar32=PC5, ar33=PC4, ar34=PC3,  
> ar35=PC2, ar36=PC1, ar37=PC0, ar38=PD7, ar39=PG2,  
> ar40=PG1, ar41=PG0, ar42=PL7, ar43=PL6, ar44=PL5,  
> ar45=PL4, ar46=PL3, ar47=PL2, ar48=PL1, ar49=PL0,  
> ar50=PB3, ar51=PB2, ar52=PB1, ar53=PB0, ar54=PF0,  
> ar55=PF1, ar56=PF2, ar57=PF3, ar58=PF4, ar59=PF5,  
> ar60=PF6, ar61=PF7, ar62=PK0, ar63=PK1, ar64=PK2,  
> ar65=PK3, ar66=PK4, ar67=PK5, ar68=PK6, ar69=PK7,  
> analog0=PF0, analog1=PF1, analog2=PF2, analog3=PF3, analog4=PF4,  
> analog5=PF5, analog6=PF6, analog7=PF7, analog8=PK0, analog9=PK1,  
> analog10=PK2, analog11=PK3, analog12=PK4, analog13=PK5, analog14=PK6,  
> analog15=PK7,  
> # Marlin adds these additional aliases  
> ml70=PG4, ml71=PG3, ml72=PJ2, ml73=PJ3, ml74=PJ7,  
> ml75=PJ4, ml76=PJ5, ml77=PJ6, ml78=PE2, ml79=PE6,  
> ml80=PE7, ml81=PD4, ml82=PD5, ml83=PD6, ml84=PH2,  
> ml85=PH7