What is the problem?
Can't connect from Raspberry Pi zero 2 w to Prusa Mk3+ via serial usb connection. "No more candidates to test, and no working port/baudrate combination detected." is the result over and over. So many people have apparently had a similar issue, that I thought it would be easy to figure out! I've researched and researched (help!)
What did you already try to solve it?
I disabled the system console connection to the serial port via RASPI-CONFIG ... saying NO to System Console use of Serial Port and Yes to Enabling Serial port (2nd question).
I did an ls -l /dev to view where the serial ports were connected (trimmed off the start and end of the output:
pi@raspberrypi:~ $ ls -l /dev
pi@raspberrypi:~ $ ls -l /dev
brw-rw---- 1 root disk 1, 7 Apr 7 19:48 ram7
brw-rw---- 1 root disk 1, 8 Apr 7 19:48 ram8
brw-rw---- 1 root disk 1, 9 Apr 7 19:48 ram9
crw-rw-rw- 1 root root 1, 8 Apr 7 19:48 random
drwxr-xr-x 2 root root 60 Dec 31 1969 raw
crw-rw-r-- 1 root netdev 10, 242 Apr 7 19:48 rfkill
lrwxrwxrwx 1 root root 7 Apr 7 19:48 serial0 -> ttyAMA0
lrwxrwxrwx 1 root root 5 Apr 7 19:48 serial1 -> ttyS0
drwxrwxrwt 2 root root 40 Feb 14 2019 shm
drwxr-xr-x 2 root root 80 Apr 7 19:48 snd
lrwxrwxrwx 1 root root 15 Feb 14 2019 stderr -> /proc/self/fd/2
lrwxrwxrwx 1 root root 15 Feb 14 2019 stdin -> /proc/self/fd/0
lrwxrwxrwx 1 root root 15 Feb 14 2019 stdout -> /proc/self/fd/1
crw-rw-rw- 1 root tty 5, 0 Apr 7 19:50 tty
crw--w---- 1 root tty 4, 0 Apr 7 19:48 tty0
crw--w---- 1 root tty 4, 1 Apr 7 19:48 tty1
crw--w---- 1 root tty 4, 10 Apr 7 19:48 tty10
crw--w---- 1 root tty 4, 11 Apr 7 19:48 tty11
crw--w---- 1 root tty 4, 12 Apr 7 19:48 tty12
crw--w---- 1 root tty 4, 13 Apr 7 19:48 tty13
crw--w---- 1 root tty 4, 14 Apr 7 19:48 tty14
crw--w---- 1 root tty 4, 15 Apr 7 19:48 tty15
crw--w---- 1 root tty 4, 16 Apr 7 19:48 tty16
crw--w---- 1 root tty 4, 17 Apr 7 19:48 tty17
crw--w---- 1 root tty 4, 18 Apr 7 19:48 tty18
crw--w---- 1 root tty 4, 19 Apr 7 19:48 tty19
crw--w---- 1 root tty 4, 2 Apr 7 19:48 tty2
crw--w---- 1 root tty 4, 20 Apr 7 19:48 tty20
crw--w---- 1 root tty 4, 21 Apr 7 19:48 tty21
crw--w---- 1 root tty 4, 22 Apr 7 19:48 tty22
crw--w---- 1 root tty 4, 23 Apr 7 19:48 tty23
crw--w---- 1 root tty 4, 24 Apr 7 19:48 tty24
crw--w---- 1 root tty 4, 25 Apr 7 19:48 tty25
crw--w---- 1 root tty 4, 26 Apr 7 19:48 tty26
crw--w---- 1 root tty 4, 27 Apr 7 19:48 tty27
crw--w---- 1 root tty 4, 28 Apr 7 19:48 tty28
crw--w---- 1 root tty 4, 29 Apr 7 19:48 tty29
crw--w---- 1 root tty 4, 3 Apr 7 19:48 tty3
crw--w---- 1 root tty 4, 30 Apr 7 19:48 tty30
crw--w---- 1 root tty 4, 31 Apr 7 19:48 tty31
crw--w---- 1 root tty 4, 32 Apr 7 19:48 tty32
crw--w---- 1 root tty 4, 33 Apr 7 19:48 tty33
crw--w---- 1 root tty 4, 34 Apr 7 19:48 tty34
crw--w---- 1 root tty 4, 35 Apr 7 19:48 tty35
crw--w---- 1 root tty 4, 36 Apr 7 19:48 tty36
crw--w---- 1 root tty 4, 37 Apr 7 19:48 tty37
crw--w---- 1 root tty 4, 38 Apr 7 19:48 tty38
crw--w---- 1 root tty 4, 39 Apr 7 19:48 tty39
crw--w---- 1 root tty 4, 4 Apr 7 19:48 tty4
crw--w---- 1 root tty 4, 40 Apr 7 19:48 tty40
crw--w---- 1 root tty 4, 41 Apr 7 19:48 tty41
crw--w---- 1 root tty 4, 42 Apr 7 19:48 tty42
crw--w---- 1 root tty 4, 43 Apr 7 19:48 tty43
crw--w---- 1 root tty 4, 44 Apr 7 19:48 tty44
crw--w---- 1 root tty 4, 45 Apr 7 19:48 tty45
crw--w---- 1 root tty 4, 46 Apr 7 19:48 tty46
crw--w---- 1 root tty 4, 47 Apr 7 19:48 tty47
crw--w---- 1 root tty 4, 48 Apr 7 19:48 tty48
crw--w---- 1 root tty 4, 49 Apr 7 19:48 tty49
crw--w---- 1 root tty 4, 5 Apr 7 19:48 tty5
crw--w---- 1 root tty 4, 50 Apr 7 19:48 tty50
crw--w---- 1 root tty 4, 51 Apr 7 19:48 tty51
crw--w---- 1 root tty 4, 52 Apr 7 19:48 tty52
crw--w---- 1 root tty 4, 53 Apr 7 19:48 tty53
crw--w---- 1 root tty 4, 54 Apr 7 19:48 tty54
crw--w---- 1 root tty 4, 55 Apr 7 19:48 tty55
crw--w---- 1 root tty 4, 56 Apr 7 19:48 tty56
crw--w---- 1 root tty 4, 57 Apr 7 19:48 tty57
crw--w---- 1 root tty 4, 58 Apr 7 19:48 tty58
crw--w---- 1 root tty 4, 59 Apr 7 19:48 tty59
crw--w---- 1 root tty 4, 6 Apr 7 19:48 tty6
crw--w---- 1 root tty 4, 60 Apr 7 19:48 tty60
crw--w---- 1 root tty 4, 61 Apr 7 19:48 tty61
crw--w---- 1 root tty 4, 62 Apr 7 19:48 tty62
crw--w---- 1 root tty 4, 63 Apr 7 19:48 tty63
crw--w---- 1 root tty 4, 7 Apr 7 19:48 tty7
crw--w---- 1 root tty 4, 8 Apr 7 19:48 tty8
crw--w---- 1 root tty 4, 9 Apr 7 19:48 tty9
crw-rw---- 1 root dialout 204, 64 Apr 7 19:50 ttyAMA0
crw------- 1 root root 5, 3 Apr 7 19:48 ttyprintk
crw-rw---- 1 root dialout 4, 64 Apr 7 19:48 ttyS0
crw------- 1 root root 10, 239 Apr 7 19:48 uhid
crw------- 1 root root 10, 223 Apr 7 19:48 uinput
crw-rw-rw- 1 root root 1, 9 Apr 7 19:48 urandom
drwxr-xr-x 3 root root 60 Apr 7 19:48 v4l
crw-rw---- 1 root video 243, 0 Apr 7 19:48 vchiq
crw-rw---- 1 root video 247, 0 Apr 7 19:48 vcio
crw------- 1 root root 248, 0 Apr 7 19:48 vc-mem
crw-rw---- 1 root tty 7, 0 Apr 7 19:48 vcs
crw-rw---- 1 root tty 7, 1 Apr 7 19:48 vcs1
crw-rw---- 1 root tty 7, 2 Apr 7 19:48 vcs2
crw-rw---- 1 root tty 7, 3 Apr 7 19:48 vcs3
crw-rw---- 1 root tty 7, 4 Apr 7 19:48 vcs4
crw-rw---- 1 root tty 7, 5 Apr 7 19:48 vcs5
crw-rw---- 1 root tty 7, 6 Apr 7 19:48 vcs6
crw-rw---- 1 root tty 7, 128 Apr 7 19:48 vcsa
crw-rw---- 1 root tty 7, 129 Apr 7 19:48 vcsa1
crw-rw---- 1 root tty 7, 130 Apr 7 19:48 vcsa2
crw-rw---- 1 root tty 7, 131 Apr 7 19:48 vcsa3
crw-rw---- 1 root tty 7, 132 Apr 7 19:48 vcsa4
crw-rw---- 1 root tty 7, 133 Apr 7 19:48 vcsa5
crw-rw---- 1 root tty 7, 134 Apr 7 19:48 vcsa6
crw-rw---- 1 root video 10, 62 Apr 7 19:48 vcsm-cma
These are the only things set in the /boot/config.txt file. (added the line to disable bluetooth which someone wrote.
# Enable audio (loads snd_bcm2835)
dtparam=audio=on
[pi4]
# Enable DRM VC4 V3D driver on top of the dispmanx display stack
dtoverlay=vc4-fkms-v3d
max_framebuffers=2
[all]
#dtoverlay=vc4-fkms-v3d
# enable raspicam
start_x=1
gpu_mem=128
enable_uart=1
dtoverlay=disable-bt
Also I tried this as it seemed to be suggested somewhere, removing the "console=tty1"
console=tty1 root=PARTUUID=f73abba5-02 rootfstype=ext4 elevator=deadline fsck.repair=yes rootwait
so it now is changed to:
root=PARTUUID=f73abba5-02 rootfstype=ext4 elevator=deadline fsck.repair=yes rootwait
After many attempts, and much googling all over the web for a couple of days now, I started to suspect maybe having cable or power supply problems ... I purchased a new USB cable and micro usb to female usb adapter, as well as a new power supply that is a full 3A (not a charger). I have a few rpi zero 2 w's and swapped with a different one to rule out a board problem. Nothing has helped.
Not too long ago I updated the Prusa firmware via USB from my PC. So this seems like it validates that even the older usb cable was working and the Prusa is communicating.
I am trying to connect via the regular usb connection, NOT the GPIO pins, so the RPI is = off on the prusa (just in case I tried it set to "on" with no difference)
I really thought I could solve this on my own ... really confused now. I've tried so many things and started over many times over the last two days. I've probably made some dumb error ... simply overlooked something. Any help appreciated!
Have you tried running in safe mode?
yes
Did running in safe mode solve the problem?
no
Systeminfo Bundle
You can download this in OctoPrint's System Information dialog ... no bundle, no support!)
octoprint-systeminfo-20220407185309.zip (1022.7 KB)
Additional information about your setup
OctoPrint version, OctoPi version, printer, firmware, browser, operating system, ... as much data as possible
The OctoPrint version is the latest release
- OctoPrint 1.7.3
- Python 3.7.3
- OctoPi 0.18.0
The Prusa has the latest firmware is printing well via usb card.
Here is the result of my last attempt to connect ...
Changing monitoring state from "Offline" to "Detecting serial connection"
Performing autodetection with 4 port/baudrate candidates: /dev/ttyS0@115200, /dev/ttyS0@250000, /dev/ttyAMA0@115200, /dev/ttyAMA0@250000
Trying port /dev/ttyS0, baudrate 115200
Connecting to port /dev/ttyS0, baudrate 115200
Unexpected error while connecting to serial port /dev/ttyS0, baudrate 115200 from hook default: SerialException: 'Could not configure port: (5, 'Input/output error')' @ comm.py:_open_serial:3779
Could not open port /dev/ttyS0, baudrate 115200, skipping
Trying port /dev/ttyS0, baudrate 250000
Connecting to port /dev/ttyS0, baudrate 250000
Unexpected error while connecting to serial port /dev/ttyS0, baudrate 250000 from hook default: SerialException: 'Could not configure port: (5, 'Input/output error')' @ comm.py:_open_serial:3779
Could not open port /dev/ttyS0, baudrate 250000, skipping
Trying port /dev/ttyAMA0, baudrate 115200
Connecting to port /dev/ttyAMA0, baudrate 115200
Handshake attempt #1 with timeout 2.0s
Connected to: Serial<id=0x6ebc0e30, open=True>(port='/dev/ttyAMA0', baudrate=115200, bytesize=8, parity='N', stopbits=1, timeout=2.0, xonxoff=False, rtscts=False, dsrdtr=False), starting monitor
Send: N0 M110 N0*125
Handshake attempt #2 with timeout 2.0s
Send: N0 M110 N0*125
Handshake attempt #3 with timeout 2.0s
Send: N0 M110 N0*125
Trying port /dev/ttyAMA0, baudrate 250000
Handshake attempt #1 with timeout 2.0s
Send: N0 M110 N0*125
Handshake attempt #2 with timeout 2.0s
Send: N0 M110 N0*125
Handshake attempt #3 with timeout 2.0s
Send: N0 M110 N0*125
Changing monitoring state from "Detecting serial connection" to "Error"
Changing monitoring state from "Error" to "Offline after error"
Connection closed, closing down monitor
