RaspberryPi Zero / Zero W and UART plugin

[christianF]

Hello, I have problems with RaspberryPi Zero / Zero W and the UART plugin on ttyAMA0.
I use the QLC+ Buster Image.
Sometimes everything works wonderfully but after the next reboot not anymore.
I have an oscilloscope connected to the TX pin from the RPi, the baud rate then fluctuates when the DMX output stalls.
To rule out that it is due to ttyS0 / BT /miniUART I have also configured an RPi Zero without BT/WLAN with a fresh Buster image. Again, the problem often appears after a reboot.
Does anyone have an idea?

my cmdline.txt
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dwc_otg.lpm_enable=0 console=tty1 root=PARTUUID=76fe5b12-02 rootfstype=ext4 elevator=deadline fsck.repair=yes rootwait quiet

my config.txt
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# For more options and information see
# http://rpf.io/configtxt
# Some settings may impact device functionality. See link above for details

# uncomment if you get no picture on HDMI for a default "safe" mode
#hdmi_safe=1

# uncomment this if your display has a black border of unused pixels visible
# and your display can output without overscan
#disable_overscan=1

# uncomment the following to adjust overscan. Use positive numbers if console
# goes off screen, and negative if there is too much border
#overscan_left=16
#overscan_right=16
#overscan_top=16
#overscan_bottom=16

# uncomment to force a console size. By default it will be display's size minus
# overscan.
#framebuffer_width=1280
#framebuffer_height=720

# uncomment if hdmi display is not detected and composite is being output
#hdmi_force_hotplug=1

# uncomment to force a specific HDMI mode (this will force VGA)
#hdmi_group=1
#hdmi_mode=1

# uncomment to force a HDMI mode rather than DVI. This can make audio work in
# DMT (computer monitor) modes
#hdmi_drive=2

# uncomment to increase signal to HDMI, if you have interference, blanking, or
# no display
#config_hdmi_boost=4

# uncomment for composite PAL
#sdtv_mode=2

#uncomment to overclock the arm. 700 MHz is the default.
#arm_freq=800

# Uncomment some or all of these to enable the optional hardware interfaces
#dtparam=i2c_arm=on
#dtparam=i2s=on
dtparam=spi=on

# Uncomment this to enable the lirc-rpi module
#dtoverlay=lirc-rpi

# Additional overlays and parameters are documented /boot/overlays/README

# 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

# QLC+ workaround for headless case
hdmi_force_hotplug=1

enable_uart=1
init_uart_clock=16000000

[christianF]

Hi, I have not been able to fix the problem. If someone has a similar problem I describe here my workaround:
I have enabled "Run standalone OLA daemon" in QLC+ Inputs/Outputs at OLA and send ArtNet output via 127.0.0.1 Universe 0.
I have set OLA to "Input: ArtNet" and "Output: UART native DMX" on /dev/ttyAMA0.

/boot/cmdline.txt

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dwc_otg.lpm_enable=0 console=tty1 root=PARTUUID=76fe5b12-02 rootfstype=ext4 elevator=deadline fsck.repair=yes rootwait quiet

/boot/config.txt

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init_uart_clock=16000000
enable_uart=1

/etc/ola/ola-uartdmx.conf

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/dev/ttyAMA0-break = 100
/dev/ttyAMA0-malf = 24000
device = /dev/ttyAMA0
enabled = true

/etc/ola/ola-artnet.conf

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always_broadcast = true
enabled = true
ip = 127.0.0.1
long_name = Q Light Controller Plus - ArtNet interface
net = 0
output_ports = 4
short_name = QLC+
subnet = 0
use_limited_broadcast = false
use_loopback = true

However, I am unsure if I am using OLA correctly. I assumed that I select "OLA Universe 1" as output in the Inputs/Outputs tab in QLC+ and QLC+ then communicates with OLA without using ArtNet loopback. On the tutorial page of the OLA plugin (https://www.qlcplus.org/docs/html_en_EN/olaplugin.html) it says "When pressing the configuration button over a OLA output line, a small popup window will appear showing the basic information of how QLC+ outputs are mapped against OLA universes.".
For me there is no mapping information displayed (see attached image).

My workaround works, but maybe someone can point me in the right direction on how to link QLC+ and OLA correctly.