Lost connection to Duet Issue 3.3-rc1/3.3beta3.1(dropbox)

tristanryerparke

After dealing with a bunch of unrelated hardware and software issues for the past few days (all my own fault but still annoying) I have run into an issue with my duet3 + pi4. It was up and running perfectly last night with 3.3beta3.1 (from dropbox). This morning when I booted up the machine and tried to home it, I received this error in DWC:

Lost connection to Duet (Board is not available (no header))

After restarting, I am able to jog the machine around(without homing), send commands and view/edit/download files in dwc. But clicking of any homing button or sending G28 throws the error and I need to reboot both pi and duet to reconnect.
Since I was running the bleeding-edge software version and the 3.3rc1 update was just released, I installed it to see if it would fix the issue. I used sudo apt-get update since I was subscribed to the unstable feed.
However, the issue still remains. In order to try and fix I have tried the following:

Reflash the firmware with bossa
Tried a new sd card with fresh duetpi image.
Tried several different orientations of ribbon cable/pi placement and cleaned pins on pi and duet with a light air blast.
Changed my hostname and machine name to only have one dash ("tristan-painting-machine" to "tristan-paintingmachine" As seen in this article:
https://forum.duet3d.com/topic/18158/lost-connection-to-duet3-sbc

I enabled debugging on the pi and have these two files:
duetcontrolserver.txt duetwebserver.txt
I also have the M122 report with a suspicious last reset:

5/1/2021, 1:00:25 PM: Connected to tristan-paintingmachine.local
5/1/2021, 1:00:30 PM: m122: === Diagnostics ===
RepRapFirmware for Duet 3 MB6HC version 3.3RC1 (2021-05-01 09:12:50) running on Duet 3 MB6HC v1.01 or later (SBC mode)
Board ID: 08DJM-956L2-G43S8-6J9D6-3S46R-KU2AD
Used output buffers: 1 of 40 (13 max)
=== RTOS ===
Static ram: 150680
Dynamic ram: 61468 of which 0 recycled
Never used RAM 93188, free system stack 200 words
Tasks: SBC(ready,5.7%,310) HEAT(delaying,0.0%,375) Move(notifyWait,0.0%,352) CanReceiv(notifyWait,0.0%,907) CanSender(notifyWait,0.0%,373) CanClock(delaying,0.0%,341) TMC(notifyWait,7.2%,93) MAIN(running,87.0%,1264) IDLE(ready,0.1%,29), total 100.0%
Owned mutexes: HTTP(MAIN)
=== Platform ===
Last reset 00:02:49 ago, cause: power up
Last software reset at 2021-05-01 17:55, reason: MemoryProtectionFault mmarValid daccViol, GCodes spinning, available RAM 93188, slot 2
Software reset code 0x4163 HFSR 0x00000000 CFSR 0x00000082 ICSR 0x00400804 BFAR 0x00000004 SP 0x2041af48 Task MAIN Freestk 1521 ok
Stack: 2042b2b4 2042b334 2042b348 00000000 20424c20 00455f33 0044b182 89070000 00000000 2042b434 00000000 00000000 00000000 20423f20 00000001 00000000 2041b0f0 ffffffed 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
Error status: 0x00
Aux0 errors 0,0,0
Aux1 errors 0,0,0
Step timer max interval 128
MCU temperature: min 40.8, current 44.3, max 44.4
Supply voltage: min 24.1, current 24.2, max 24.2, under voltage events: 0, over voltage events: 0, power good: yes
12V rail voltage: min 12.1, current 12.1, max 12.1, under voltage events: 0
Heap OK, handles allocated/used 99/1, heap memory allocated/used/recyclable 2048/12/0, gc cycles 0
Driver 0: position 0, standstill, reads 25059, writes 18 timeouts 0, SG min/max 0/0
Driver 1: position 0, standstill, reads 25062, writes 16 timeouts 0, SG min/max 0/0
Driver 2: position 0, standstill, reads 25064, writes 14 timeouts 0, SG min/max 0/0
Driver 3: position 0, standstill, reads 25064, writes 14 timeouts 0, SG min/max 0/0
Driver 4: position 0, standstill, reads 25064, writes 14 timeouts 0, SG min/max 0/0
Driver 5: position 0, standstill, reads 25067, writes 11 timeouts 0, SG min/max 0/0
Date/time: 2021-05-01 18:00:29
Slowest loop: 0.45ms; fastest: 0.04ms
=== Storage ===
Free file entries: 10
SD card 0 not detected, interface speed: 37.5MBytes/sec
SD card longest read time 0.0ms, write time 0.0ms, max retries 0
=== Move ===
DMs created 125, maxWait 0ms, bed compensation in use: none, comp offset 0.000
=== MainDDARing ===
Scheduled moves 0, completed moves 0, hiccups 0, stepErrors 0, LaErrors 0, Underruns [0, 0, 0], CDDA state -1
=== AuxDDARing ===
Scheduled moves 0, completed moves 0, hiccups 0, stepErrors 0, LaErrors 0, Underruns [0, 0, 0], CDDA state -1
=== Heat ===
Bed heaters = -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1, chamberHeaters = -1 -1 -1 -1
=== GCodes ===
Segments left: 0
Movement lock held by null
HTTP* is doing "M122" in state(s) 0
Telnet is idle in state(s) 0
File is idle in state(s) 0
USB is idle in state(s) 0
Aux is idle in state(s) 0
Trigger* is idle in state(s) 0
Queue is idle in state(s) 0
LCD is idle in state(s) 0
SBC is idle in state(s) 0
Daemon is idle in state(s) 0
Aux2 is idle in state(s) 0
Autopause is idle in state(s) 0
Code queue is empty.
=== CAN ===
Messages queued 857, send timeouts 0, received 11, lost 0, longest wait 1ms for reply type 6018, peak Tx sync delay 6, free buffers 49 (min 48)
=== SBC interface ===
State: 4, failed transfers: 0
Last transfer: 2ms ago
RX/TX seq numbers: 5082/5082
SPI underruns 0, overruns 0
Number of disconnects: 0, IAP RAM available 0x2c90c
Buffer RX/TX: 0/0-0
=== Duet Control Server ===
Duet Control Server v3.3-rc1
Code buffer space: 4096
Configured SPI speed: 8000000 Hz
Full transfers per second: 18.44
Codes per second: 0.15
Maximum length of RX/TX data transfers: 3287/308

Any advice or solutions?
I'm tempted to go back to 3.2.2 but am really enjoying the variables.
Cheers,
T

dc42

This appears to be the same issue as https://forum.duet3d.com/topic/23029/3-3-rc1-homing-causes-controller-reset. Please continue in that thread.