Connecting UART | 3D Printing | Page 1

somber lintel May 19, 2024, 11:21 AM

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I'm trying to connect an SKR mini E3 V3 to the UART3 of an Orange Pi 3 LTS.
I have wired everything correctly. Ground to ground, 5v to 5v, RX to TX, TX2 to RX2.
The pi powers on, all seems well, except -> I can't connect to the MCU in the klipper interface.

When I disconnect the TX and RX and connect a usb, it connects, but then, with RX and TX again, no connection.

I've modified my /boot/armbianEnv.txt to have:
overlays=uart3

and in my printer.cfg, I have
[mcu]
serial: /dev/ttyS3

Yet, no connection. I'm sure I've missed something, but I haven't a clue where to even begin.
Any help is highly appreciated.

silent gateBOT May 19, 2024, 11:21 AM

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somber lintel I'm trying to connect an SKR mini E3 V3 to the UART3 of an Orange Pi 3 LTS. I ha...

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AI Help

It seems like you have followed the correct steps for connecting the SKR mini E3 V3 to the UART3 of the Orange Pi 3 LTS. The fact that you are able to connect via USB but not through the UART connection suggests that there may be a configuration issue related to the UART communication.

To troubleshoot this issue, you may want to check the baud rate settings on both the SKR mini E3 V3 and the Orange Pi 3 LTS and ensure they are set to the same value. Additionally, you may want to check if there are any specific UART settings required for the Klipper firmware to communicate with the SKR board.

If you are unable to resolve the issue after checking these settings, I recommend reaching out to the Klipper community or forums for further assistance as they may have encountered similar issues and can provide more specific guidance.

gray zodiac May 19, 2024, 11:23 AM

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It'd be a good idea to check if the SKR & oPi both use the same voltage for GPIO-
What this means is you need to check if the GPIO from the oPi is 5v or 3V3

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The SKR should be 3V3 since I see an STM32 chip.

round wedge May 19, 2024, 11:24 AM

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did you reflash the mainboard?

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you have to go to the make menuconfig and select serial connection and your hotend heatsink cooling pin

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then flash the bin on your board

somber lintel May 19, 2024, 11:29 AM

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I see. I haven't done that.

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As for the voltage of the GPIO, I don't even know how I'd check for that tbh.

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I don't have a volt-meter.

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I'll ask chatgpt

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Alright then, I'll have to reflash later tonight and hope I can make this work. I can't really do a backup, but I kind of feel like it's whatever.
My installation of klipper is kind of outdated and corrupt, and the printer.cfg uploaded by bassamanator looks new. I should probably start fresh anyway.

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In the meanwhile, I'm going to go get some dinner.

round wedge May 19, 2024, 11:39 AM

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somber lintel I see. I haven't done that.

that's why

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but also I wouldn't connect power, just power the pi separately

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not worth the risks

somber lintel May 19, 2024, 11:47 AM

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Oh. It seemed to be fine so far, but.. what risks?

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What about connecting it directly to the psu using a step-down converter?

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I kind of wanted to see if I could use the usb c for a peripheral.

round wedge May 19, 2024, 11:59 AM

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somber lintel Oh. It seemed to be fine so far, but.. what risks?

the board can't really supply a full size pi with power

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a pi zero sure

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plus by powering the gpio you go around the usb power safety measures

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I just use one of these

somber lintel May 19, 2024, 12:56 PM

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Hmm, that kinda throws off my plan to use usb c for peripherals.

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I guess it can't be helped.

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Unless, does a step-down converter have protections similar to a USB?

round wedge May 19, 2024, 1:25 PM

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what do you need peripherals for?

round wedge May 19, 2024, 1:25 PM

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somber lintel Unless, does a step-down converter have protections similar to a USB?

you'd still skip the usb

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also not familiar with the orange in particular but for the rpi the charging port can't even be used for devices

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needs 3A

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the skr is like 1

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that port is probably just power in only

somber lintel May 19, 2024, 2:12 PM

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round wedge what do you need peripherals for?

I've got 3 USB ports, and one USB C. The USB C was/is used for power, 1 usb was used for the MCU, and two were used for cameras.
But, I have two boards that need usb. ERCF board, and a voron klipper expansion board. I have yet to familiarize myself with either, but I was really hoping to avoid using a USB hub.

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the USB ports on the pi are also 2.0 port x 1, and two usb 3.0 ports. Come to think of it, yeah if I power the thing using GPIO, it probably can't power both webcams - though honestly that endoscope nozzle cam gets really hot, maybe if it didn't have so much power it'd run cooler.

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but probably at the cost of functionality.

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I'd still rather power it through the PSU or something, rather than having it take up a power-bar slot. I have to crack open the PSU anyway to power the expansion board....

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Maybe I can figure something out.

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Maybe one of those outlet to USB adapters.

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Or maybe I can just embed the current pi adapter inside the PSU.

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https://tenor.com/view/electricuted-amplifier-holyshit-zapped-electricity-gif-22474359

Tenor

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It'll be okay

silent gateBOT May 19, 2024, 4:32 PM

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somber lintel May 20, 2024, 8:32 PM

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So I can't figure this out. I reflashed my printer's MCU using this:

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and finally, /boot/armbianEnv.txt

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I'm kind of at a loss. I don't know what else to do at this point.

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When I comment out the baud in printer.cfg, It just fails to connect to the MCU.
I'm not sure why there's even a difference, as the pins of the orange pi's uart are supposed to be 115200 by default, though I honestly have no idea.

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Any help is highly appreciated. Thank you.

round wedge May 20, 2024, 8:36 PM

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serial: /dev/ttyAMA0
baud: 250000
restart_method: command```

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I used that baud anyway

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in the low level thing you put the hotend fan pin

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whichever you chosen

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I also used these pins

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in the screen port

somber lintel May 20, 2024, 8:39 PM

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Do I need to reflash yet again, and change the baud to 250000?

round wedge May 20, 2024, 8:39 PM

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ye

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and give the correct pin

somber lintel May 20, 2024, 8:41 PM

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?

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Do I need to change anything else here?

round wedge May 20, 2024, 8:41 PM

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should be it

somber lintel May 20, 2024, 8:41 PM

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alright, just compiling this, then I'll flash it.

round wedge May 20, 2024, 8:42 PM

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the uart pins should be fine as well but if that doesn't work use the tx/rx in the exp port

somber lintel May 20, 2024, 8:46 PM

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Hmm, looks like that didn't work.

round wedge May 20, 2024, 8:46 PM

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you have rx going to tx right?

somber lintel May 20, 2024, 8:46 PM

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yes

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ground to ground

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but I'm powering through the USB-C

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no 5v pin connected

round wedge May 20, 2024, 8:47 PM

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idk if you even need gnd then

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do you have serial connection configured on the orange pi?

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not sure how that one works tho

somber lintel May 20, 2024, 8:48 PM

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I have no idea

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I don't even know how to check that

round wedge May 20, 2024, 8:49 PM

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https://klipper.discourse.group/t/btt-skr-mini-e3-v3-and-orange-pi-zero-3-uart/12084

Klipper

BTT skr mini e3 v3 and orange pi zero 3 UART

Basic Information: Printer Model: Ender 3 Pro MCU / Printerboard: BTT skr mini e3 v3, orange pi zero 3 klippy.log klippy.log (73.8 KB) 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. M...

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sends you over to reddit on how to do it

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or the orange pi manual

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http://www.orangepi.org/orangepiwiki/index.php/Orange_Pi_Zero_3#26pin_UART_test

Orange Pi Zero 3

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somber lintel May 20, 2024, 8:50 PM

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zero 3?

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mine's an orange pi 3 LTS

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does it matter?

round wedge May 20, 2024, 8:50 PM

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thonk orange orange

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no idea tbh

somber lintel May 20, 2024, 8:51 PM

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I'm just gonna follow to the best of my ability and see if things fall into place.

round wedge May 20, 2024, 8:52 PM

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or ask in an orange pi specific server

somber lintel May 20, 2024, 8:53 PM

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It looks like it's enabled.

somber lintel May 20, 2024, 9:12 PM

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Yeah, the orange pi discord is basically dead.

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I'll just have to ask around everywhere I can.

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I'm absolutely losing my mind with this.

round wedge May 20, 2024, 10:09 PM

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unfortunately my linux knowledge is 0

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I'd try the Tx/Rx pins in the screen port tho

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maybe?

#Connecting UART