frequently asked questions - MCU connection issues
I have been working on a FAQ for this: I hope some of it helps
* MCU POWER JUMPER was not actually removed. If you don't remove this jumper, the Octopus board is unable to use USB to communicate with the PI * edit your printer.cfg. If you didn't edit your printer.cfg to match your setup, klipper will be unable to connect to the octopus board. Go through each line of the printer.cfg file and uncomment the lines that are needed for your setup. * Bad wiring. There are several warnings about fixing the endstops wiring. If you fail to do this you will short your board and cause damage. There may also be other wiring/shorts. If you are still having issues disconnect everything but power to the octopus board and the USB to the PI and then try again. If the PI complains about temperature out of range (this is expected because you disconnected your thermistors) then you know you had a wiring issue. Shutdown and reconnect one item, then turn everything back on. Continue to do this until you get the MCU connect error again, and whatever that last item you connected is the problem. * Bad USB Cable. You need to connect USB A (the Big rectangular plug) on the PI, and USB C (the very small plug like the one you use on your cell phone) to the Octopus board. If you already have it connected like this, try a different USB Cable as the one you are using might be broken or power only.
If none of that still fixes your issue, you will need to SSH into your raspberry PI and run some commands: * SSH into your PI * disconnect your octopus board * run
* MCU POWER JUMPER was not actually removed. If you don't remove this jumper, the Octopus board is unable to use USB to communicate with the PI * edit your printer.cfg. If you didn't edit your printer.cfg to match your setup, klipper will be unable to connect to the octopus board. Go through each line of the printer.cfg file and uncomment the lines that are needed for your setup. * Bad wiring. There are several warnings about fixing the endstops wiring. If you fail to do this you will short your board and cause damage. There may also be other wiring/shorts. If you are still having issues disconnect everything but power to the octopus board and the USB to the PI and then try again. If the PI complains about temperature out of range (this is expected because you disconnected your thermistors) then you know you had a wiring issue. Shutdown and reconnect one item, then turn everything back on. Continue to do this until you get the MCU connect error again, and whatever that last item you connected is the problem. * Bad USB Cable. You need to connect USB A (the Big rectangular plug) on the PI, and USB C (the very small plug like the one you use on your cell phone) to the Octopus board. If you already have it connected like this, try a different USB Cable as the one you are using might be broken or power only.
If none of that still fixes your issue, you will need to SSH into your raspberry PI and run some commands: * SSH into your PI * disconnect your octopus board * run
dmesg -w and while it is running, plug your octopus board into your PI
* examine the output and see if there are errors trying to connect. If there, it will depend on the error what the next step is.18 Replies
fair-rose•17mo ago
OK, thanks! I have lots of images showing jumpers on the Octopus PRO, but none of them show the location of the MCU POWER JUMPER. Where is it please? Thanks again!
Check the owners manual
It's a V_USB (will be called similar in the manual / pinout) jumper, all it does is connect 5V with USB 5V (you don't want this and 24V connected at the same time).
fair-rose•17mo ago
Thank you, Sir! Please, I need some help. The Octopus PRO Manual, and dozens of on-line images of Octopus PRO wiring make no mention of this jumper. This is my first 3D printer, but I have been building electronics, and writing computer code for about 50 years. I've built a Standard Rat Rig V-Core 3 500. My problem is that Klipper won't start. I have a Raspberry Pi 3 B+ connected to the Octopus via USB-C. There are several LEDs illuminated on the Octopus, including green motor power and a rapidly flashing red "STATUS" LED. I have a Windows 10 lap-top that appears to be communicating very well with RatOS via WiFi. Since I had no knowledge of this jumper, have I damaged the Octopus? Thank you for your help, Mr. MiklSchmidt!
please start a new post
correct-apricot•17mo ago
OKay, I had figured out that hotend thermistor 's wires was connected and that was a shortage in the wiring.
hi i followed your procedure , thx its well described , but i cant ssh into the pi: when i get "pi@192.168.1.165's password: " i can't type anything behind this line ? would you like me to open a new post ? EDIT: since the post i got to ssh and enter the command and i got no error, what would be the course to get the cu to connect then ?
Use the configurator and follow the instructions to the letter. If it won't detect / flash correctly, try different sd cards. It's important that you do exactly what it says.
ok i tried redoing everything now i can't pass step one : "BIGTREETECH Octopus V1.1 was not detected"
That means it didn't flash correctly. All your wires are removed, sd card is formatted correctly and you tried different cards?
ok gonna do another card
thx
you probably should start your own post instead of continuing in the FAQ
If using DFu mode do you need an sd card inserted?
please make a new post
conscious-sapphire•12mo ago
hi I need help to fix the mcu connection I did searched all the web and didn't find a fix to it
pls help me
conscious-sapphire•12mo ago
and I did checked the ratrig form for it
and no luck with it
start your own post please
conscious-sapphire•12mo ago
ok