Compatibility question

The Velleman VM205 has my interest because I’m working with small digital projects with low frequency signals and I want to be able to trace those. And hey, it’s cool when you can do that with equipment that one assembled oneself, isn’t it?

So, I set out to my favourite electronics shop and bought a Raspberry Pi 3 B, and a Raspberry Pi 7 inch touchscreen display to go with it, and, of course, the VM205.

The RPI came with a pre-installed micro SD card that offered Raspbian. I installed that and got it up and running. Then I followed these instructions to connect the VM205, so SPI is enabled. I then downloaded the software from the Velleman website and, after having made it executable, tried to run it. It gives a message:

bcm2835_init: Unable to open /dev/mem: Permission denied

followed by:

Segmentation fault

The command “uname -a” gives me a kernel version of 4.9.35-v7+

Somewhere along the line I got a message about a missing library, so I had to (re-) install it, libDSL2…

Any thoughts? I would really like to use this configuration as my low-level logic analyser.

Gerard

The designer of the VM205 told me:

To test, I updated my Raspberry Pi 3 B to latest kernel version of 4.9.35-v7+.
My VM205 works fine with this latest kernel version.

The only I can suggest the customer to do is to update the firmware once again…

Dear VEL456,

As you can read in my OP, this is exactly the kernel version that I’m using. I’m happy for you that your VM205 works.

Which firmware do you mean? Would that be the “ROM” that boots an Operating System? And if so, how would this effect the workings of said OS? Where can I find instructions for this firmware update?

Gerard

I’m sorry for the inconvenience.

I think there is no need to update the OS at the moment.
You have latest kernel version installed.
There may be other solutions too…
In this thread there is some info about similar problem and solution:
https://www.element14.com/community/thread/30690/l/failed-to-open-devmem-try-checking-permissions?displayFullThread=true
There is written: "When running the program (./blink_test) as a normal user , you get the message: Failed to open /dev/mem, try checking permissions

when you run it using sudo (the super user), you don’t get the error

what this means is, the dev/mem ‘device’ is not accessible to the normal user, but it is accessible to the root (sudo) user"

Here also found similar:
“bcm2835_init: Unable to open /dev/mem: Permission denied
Segmentation fault”

Here you’ll find the instructions for updating and upgrading the Raspberry Pi kernel and firmware:
https://www.raspberrypi.org/documentation/raspbian/updating.md

OK, VEL255, first: sorry for the late response. Been busy lately…

I still have no clue what you guys mean when you talk about ‘firmware’. In my book, firmware is software that’s embedded in ROM inside whatever contraption we’re talking about, dishwashers, refrigerators, even computers (the boot-rom for example). But then again, every link that is presented here points to pages telling us how to update the Operating System (kernel and other software).

Perspective: I will certainly not pretend to know everything (duh), but have been in ICT since the late '70s and do know a thing or two about updating en upgrading.

Update and upgrade are the first commands I execute when having unboxed a new RPi. So let’s get that out of the way please? :wink:

I also tried the sudo solution, it results in the application getting very silent while nothing seems to happen…

In another terminal I can see that vm205 takes a lot of CPU (1 core I’m sure, because the other terminal is responsive…)

It does however open another task in X, called ‘[WFS210 demo]’. Does this give us any pointers?

VEL255, in a second attempt this morning, I hooked my RPi 3 up to a proper monitor instead of this 7 inch touchscreen. I started X (we do need X right, or is vm205 running on some Stand-alone tk library?) and started vm205 as sudo’er. Same happened - no dice on the screen, 100 % CPU.

I performed a ps alx > ps_vm205 and tried to upload the file here for debugging purposes. That didn’t work, because its extension was not vallid. I will paste the contents in here:

Gerard

F   UID   PID  PPID PRI  NI    VSZ   RSS WCHAN  STAT TTY        TIME COMMAND
4     0     1     0  20   0  22868  3868 -      Ss   ?          0:03 /sbin/init
1     0     2     0  20   0      0     0 -      S    ?          0:00 [kthreadd]
1     0     3     2  20   0      0     0 -      S    ?          0:00 [ksoftirqd/0]
1     0     5     2   0 -20      0     0 -      S<   ?          0:00 [kworker/0:0H]
1     0     6     2  20   0      0     0 -      S    ?          0:00 [kworker/u8:0]
1     0     7     2  20   0      0     0 -      R    ?          0:00 [rcu_sched]
1     0     8     2  20   0      0     0 -      S    ?          0:00 [rcu_bh]
1     0     9     2 -100  -      0     0 -      S    ?          0:00 [migration/0]
1     0    10     2   0 -20      0     0 -      S<   ?          0:00 [lru-add-drain]
1     0    11     2  20   0      0     0 -      S    ?          0:00 [cpuhp/0]
1     0    12     2  20   0      0     0 -      S    ?          0:00 [cpuhp/1]
1     0    13     2 -100  -      0     0 -      S    ?          0:00 [migration/1]
1     0    14     2  20   0      0     0 -      S    ?          0:00 [ksoftirqd/1]
1     0    16     2   0 -20      0     0 -      S<   ?          0:00 [kworker/1:0H]
1     0    17     2  20   0      0     0 -      S    ?          0:00 [cpuhp/2]
1     0    18     2 -100  -      0     0 -      S    ?          0:00 [migration/2]
1     0    19     2  20   0      0     0 -      S    ?          0:00 [ksoftirqd/2]
1     0    21     2   0 -20      0     0 -      S<   ?          0:00 [kworker/2:0H]
1     0    22     2  20   0      0     0 -      S    ?          0:00 [cpuhp/3]
1     0    23     2 -100  -      0     0 -      S    ?          0:00 [migration/3]
1     0    24     2  20   0      0     0 -      S    ?          0:00 [ksoftirqd/3]
1     0    25     2  20   0      0     0 -      S    ?          0:00 [kworker/3:0]
1     0    26     2   0 -20      0     0 -      S<   ?          0:00 [kworker/3:0H]
5     0    27     2  20   0      0     0 -      S    ?          0:00 [kdevtmpfs]
1     0    28     2   0 -20      0     0 -      S<   ?          0:00 [netns]
1     0    29     2  20   0      0     0 -      S    ?          0:00 [khungtaskd]
1     0    30     2  20   0      0     0 -      S    ?          0:00 [oom_reaper]
1     0    31     2   0 -20      0     0 -      S<   ?          0:00 [writeback]
1     0    32     2  20   0      0     0 -      S    ?          0:00 [kcompactd0]
1     0    33     2   0 -20      0     0 -      S<   ?          0:00 [crypto]
1     0    34     2   0 -20      0     0 -      S<   ?          0:00 [bioset]
1     0    35     2   0 -20      0     0 -      S<   ?          0:00 [kblockd]
1     0    36     2   0 -20      0     0 -      S<   ?          0:00 [watchdogd]
1     0    37     2  20   0      0     0 -      S    ?          0:00 [kworker/0:1]
1     0    38     2   0 -20      0     0 -      S<   ?          0:00 [rpciod]
1     0    39     2   0 -20      0     0 -      S<   ?          0:00 [xprtiod]
1     0    40     2  20   0      0     0 -      S    ?          0:00 [kswapd0]
1     0    41     2   0 -20      0     0 -      S<   ?          0:00 [vmstat]
1     0    42     2   0 -20      0     0 -      S<   ?          0:00 [nfsiod]
1     0    52     2   0 -20      0     0 -      S<   ?          0:00 [kthrotld]
1     0    53     2   0 -20      0     0 -      S<   ?          0:00 [bioset]
1     0    54     2   0 -20      0     0 -      S<   ?          0:00 [bioset]
1     0    55     2   0 -20      0     0 -      S<   ?          0:00 [bioset]
1     0    56     2   0 -20      0     0 -      S<   ?          0:00 [bioset]
1     0    57     2   0 -20      0     0 -      S<   ?          0:00 [bioset]
1     0    58     2   0 -20      0     0 -      S<   ?          0:00 [bioset]
1     0    59     2   0 -20      0     0 -      S<   ?          0:00 [bioset]
1     0    60     2   0 -20      0     0 -      S<   ?          0:00 [bioset]
1     0    61     2   0 -20      0     0 -      S<   ?          0:00 [bioset]
1     0    62     2   0 -20      0     0 -      S<   ?          0:00 [bioset]
1     0    63     2   0 -20      0     0 -      S<   ?          0:00 [bioset]
1     0    64     2   0 -20      0     0 -      S<   ?          0:00 [bioset]
1     0    65     2   0 -20      0     0 -      S<   ?          0:00 [bioset]
1     0    66     2   0 -20      0     0 -      S<   ?          0:00 [bioset]
1     0    67     2   0 -20      0     0 -      S<   ?          0:00 [bioset]
1     0    68     2   0 -20      0     0 -      S<   ?          0:00 [bioset]
1     0    69     2   0 -20      0     0 -      S<   ?          0:00 [bioset]
1     0    70     2   0 -20      0     0 -      S<   ?          0:00 [bioset]
1     0    71     2   0 -20      0     0 -      S<   ?          0:00 [bioset]
1     0    72     2   0 -20      0     0 -      S<   ?          0:00 [bioset]
1     0    73     2   0 -20      0     0 -      S<   ?          0:00 [bioset]
1     0    74     2   0 -20      0     0 -      S<   ?          0:00 [bioset]
1     0    75     2   0 -20      0     0 -      S<   ?          0:00 [bioset]
1     0    76     2   0 -20      0     0 -      S<   ?          0:00 [bioset]
1     0    77     2   0 -20      0     0 -      S<   ?          0:00 [iscsi_eh]
1     0    78     2   0 -20      0     0 -      S<   ?          0:00 [dwc_otg]
1     0    79     2  20   0      0     0 -      S    ?          0:00 [kworker/2:1]
1     0    80     2   0 -20      0     0 -      S<   ?          0:00 [DWC Notificatio]
1     0    81     2   1 -19      0     0 -      S<   ?          0:00 [VCHIQ-0]
1     0    82     2   1 -19      0     0 -      S<   ?          0:00 [VCHIQr-0]
1     0    83     2   0 -20      0     0 -      S<   ?          0:00 [VCHIQs-0]
1     0    84     2  20   0      0     0 -      S    ?          0:00 [VCHIQka-0]
1     0    85     2  10 -10      0     0 -      S<   ?          0:00 [SMIO]
1     0    88     2 -51   -      0     0 -      S    ?          0:00 [irq/92-mmc1]
1     0    89     2  20   0      0     0 -      S    ?          0:00 [kworker/3:3]
1     0    90     2   0 -20      0     0 -      S<   ?          0:00 [bioset]
1     0    91     2  20   0      0     0 -      S    ?          0:00 [mmcqd/0]
1     0    92     2  20   0      0     0 -      S    ?          0:00 [kworker/1:1]
1     0    93     2  20   0      0     0 -      S    ?          0:00 [kworker/2:2]
1     0    94     2  20   0      0     0 -      S    ?          0:00 [jbd2/mmcblk0p7-]
1     0    95     2   0 -20      0     0 -      S<   ?          0:00 [ext4-rsv-conver]
1     0    96     2   0 -20      0     0 -      S<   ?          0:00 [ipv6_addrconf]
1     0   116     2   0 -20      0     0 -      S<   ?          0:00 [kworker/3:1H]
1     0   118     2  20   0      0     0 -      S    ?          0:00 [kworker/u8:1]
1     0   136     2  20   0      0     0 -      S    ?          0:00 [kworker/1:2]
4     0   143     1  20   0   9928  2732 -      Ss   ?          0:00 /lib/systemd/systemd-journald
4     0   146     1  20   0  11988  3056 -      Ss   ?          0:00 /lib/systemd/systemd-udevd
1     0   206     2  20   0      0     0 -      S    ?          0:00 [spi0]
1     0   254     2   0 -20      0     0 -      S<   ?          0:00 [cfg80211]
1     0   256     2   0 -20      0     0 -      S<   ?          0:00 [brcmf_wq/mmc1:0]
1     0   257     2  20   0      0     0 -      S    ?          0:00 [brcmf_wdog/mmc1]
1     0   363     2  20   0      0     0 -      S    ?          0:00 [kworker/0:2]
1     0   373     2  20   0      0     0 -      S    ?          0:00 [kworker/u8:2]
1     0   427     2  20   0      0     0 -      S    ?          0:00 [kworker/0:3]
4     0   437     1  20   0   5068  2412 -      Ss   ?          0:00 /usr/sbin/cron -f
4   105   440     1  20   0   4004  2444 -      Ss   ?          0:00 avahi-daemon: running [galileo.local]
4  1000   442     1  25   5 182872 81472 -      SNsl ?          0:16 node-red                                                                  
4     0   447     1  20   0  32140  2692 -      Ssl  ?          0:00 /usr/sbin/rsyslogd -n
4   104   453     1  20   0   5612  3112 -      Ss   ?          0:00 /usr/bin/dbus-daemon --system --address=systemd: --nofork --nopidfile --systemd-activation
5     0   464     1  20   0   9908  1492 -      SLsl ?          0:17 /usr/bin/pigpiod -l
1   105   474   440  20   0   3872   244 -      S    ?          0:00 avahi-daemon: chroot helper
5     0   475     1  20   0   2560  1812 -      Ss   ?          0:00 /sbin/dhcpcd -q -b
1     0   518     2   0 -20      0     0 -      S<   ?          0:00 [kworker/0:1H]
5     0   519     1  20   0   7152  3288 -      Ss   ?          0:00 /sbin/wpa_supplicant -s -B -P /run/wpa_supplicant.wlan0.pid -i wlan0 -D nl80211,wext -c /etc/wpa_supplicant/wpa_supplicant.conf
4     0   549     1  20   0   3848  2468 -      Ss   ?          0:00 /lib/systemd/systemd-logind
4   112   563     1  20   0   5260  3572 -      S    ?          0:00 /usr/sbin/mosquitto -c /etc/mosquitto/mosquitto.conf
4     0   576     1  20   0   5668  2828 -      Ss   ?          0:00 /usr/bin/vncserver-x11-serviced -fg
4     0   586     1  20   0   7860  4300 -      Ss   ?          0:00 /usr/sbin/sshd -D
5 65534   596     1  20   0   2288  1468 -      Ss   ?          0:00 /usr/sbin/thd --daemon --triggers /etc/triggerhappy/triggers.d/ --socket /var/run/thd.socket --pidfile /var/run/thd.pid --user nobody /dev/input/event0 /dev/input/event1
4     0   635     1  20   0   5736  2768 -      Ss   tty1       0:00 /bin/login --   
4     0   640   576  20   0  20940 13804 -      S    ?          0:00 /usr/bin/vncserver-x11-core -service
5   106   648     1  20   0   5684  3824 -      Ss   ?          0:00 /usr/sbin/ntpd -p /var/run/ntpd.pid -g -c /var/lib/ntp/ntp.conf.dhcp -u 106:111
1     0   875     2   0 -20      0     0 -      S<   ?          0:00 [kworker/u9:0]
1     0   876     2   0 -20      0     0 -      S<   ?          0:00 [hci0]
1     0   877     2   0 -20      0     0 -      S<   ?          0:00 [hci0]
1     0   879     2   0 -20      0     0 -      S<   ?          0:00 [kworker/u9:2]
1     0   880     1  20   0   2064   148 -      S    ?          0:00 /usr/bin/hciattach /dev/serial1 bcm43xx 921600 noflow - b8:27:eb:da:8d:e7
4     0   887     1  20   0   5004  3464 -      Ss   ?          0:00 /usr/lib/bluetooth/bluetoothd
0  1000   933   442  25   5   4608  2316 wait   SN   ?          0:00 /bin/bash /usr/lib/node_modules/node-red/nodes/core/hardware/nrgpio out 31 0
0  1000   935   933  25   5   9456  5580 unix_s SN   ?          0:00 python -u /usr/lib/node_modules/node-red/nodes/core/hardware/nrgpio.py out 31 0
0  1000   936   442  25   5   4608  2316 wait   SN   ?          0:00 /bin/bash /usr/lib/node_modules/node-red/nodes/core/hardware/nrgpio out 33 0
0  1000   938   936  25   5   9456  5512 unix_s SN   ?          0:00 python -u /usr/lib/node_modules/node-red/nodes/core/hardware/nrgpio.py out 33 0
0  1000   939   442  25   5   4608  2456 wait   SN   ?          0:00 /bin/bash /usr/lib/node_modules/node-red/nodes/core/hardware/nrgpio out 35 0
0  1000   941   442  25   5   4608  2456 wait   SN   ?          0:00 /bin/bash /usr/lib/node_modules/node-red/nodes/core/hardware/nrgpio out 37 0
0  1000   942   939  25   5   9456  5588 unix_s SN   ?          0:00 python -u /usr/lib/node_modules/node-red/nodes/core/hardware/nrgpio.py out 35 0
0  1000   944   941  25   5   9456  5580 unix_s SN   ?          0:00 python -u /usr/lib/node_modules/node-red/nodes/core/hardware/nrgpio.py out 37 0
1     0   962     2   0 -20      0     0 -      S<   ?          0:00 [kworker/2:1H]
1     0   963     2   0 -20      0     0 -      S<   ?          0:00 [kworker/1:1H]
4  1000   991     1  20   0   5116  3284 SyS_ep Ss   ?          0:00 /lib/systemd/systemd --user
5  1000   995   991  20   0  24296  1232 -      S    ?          0:00 (sd-pam)  
4  1000  1000   635  20   0   6476  4368 wait   S    tty1       0:00 -bash
0  1000  1018  1000  20   0   1908  1120 wait   S+   tty1       0:00 /bin/sh /usr/bin/startx
0  1000  1040  1018  20   0   3224  1576 wait   S+   tty1       0:00 xinit /etc/X11/xinit/xinitrc -- /etc/X11/xinit/xserverrc :0 vt1 -auth /tmp/serverauth.PeCwbcKx6I
0  1000  1041  1040  20   0 194512 50240 poll_s Sl   tty1       0:02 /usr/lib/xorg/Xorg -nolisten tcp :0 vt1 -auth /tmp/serverauth.PeCwbcKx6I
0  1000  1049  1040  20   0  50768 10860 poll_s Sl   tty1       0:00 /usr/bin/lxsession -s LXDE-pi -e LXDE
1  1000  1082  1049  20   0   3696   228 -      Ss   ?          0:00 /usr/bin/ssh-agent /usr/bin/dbus-launch --exit-with-session x-session-manager
1  1000  1085     1  20   0   3688  1584 poll_s S    tty1       0:00 /usr/bin/dbus-launch --exit-with-session x-session-manager
1  1000  1086     1  20   0   5620  2276 SyS_ep Ss   ?          0:00 /usr/bin/dbus-daemon --fork --print-pid 5 --print-address 7 --session
0  1000  1092     1  20   0  31232  5504 poll_s Sl   ?          0:00 /usr/lib/gvfs/gvfsd
4     0  1096     1  20   0   8004  4128 -      S    ?          0:00 /usr/bin/vncagent service 15
0  1000  1098     1  20   0  47788  4536 futex_ Sl   ?          0:00 /usr/lib/gvfs/gvfsd-fuse /run/user/1000/gvfs -f -o big_writes
0  1000  1110  1049  20   0  21296 11908 poll_s S    tty1       0:01 openbox --config-file /home/pi/.config/openbox/lxde-pi-rc.xml
0  1000  1112  1049  20   0  30232  8556 poll_s Sl   tty1       0:00 lxpolkit
0  1000  1115  1049  20   0  93096 23868 poll_s Sl   tty1       0:01 lxpanel --profile LXDE-pi
0  1000  1116  1049  20   0 139448 22276 poll_s Sl   tty1       0:01 pcmanfm --desktop --profile LXDE-pi
1  1000  1123     1  20   0   3696   228 -      Ss   ?          0:00 /usr/bin/ssh-agent -s
4     0  1124     1  20   0  36788  6044 -      Ssl  ?          0:00 /usr/lib/policykit-1/polkitd --no-debug
4   111  1146     1  21   1  21372  2032 -      SNsl ?          0:00 /usr/lib/rtkit/rtkit-daemon
0  1000  1150     1  20   0  60616  8008 poll_s Sl   ?          0:00 /usr/lib/gvfs/gvfs-udisks2-volume-monitor
4     0  1152     1  20   0  54608  6528 -      Ssl  ?          0:00 /usr/lib/udisks2/udisksd --no-debug
4  1000  1159     1  20   0  25800 11884 poll_s S    ?          0:00 /usr/bin/vncserverui service 16
0  1000  1178     1  20   0  30408  5304 poll_s Sl   ?          0:00 /usr/lib/gvfs/gvfs-goa-volume-monitor
0  1000  1182     1  20   0  30336  5184 poll_s Sl   ?          0:00 /usr/lib/gvfs/gvfs-mtp-volume-monitor
0  1000  1186     1  20   0  31356  5588 poll_s Sl   ?          0:00 /usr/lib/gvfs/gvfs-gphoto2-volume-monitor
0  1000  1190     1  20   0  42796  6412 poll_s Sl   ?          0:00 /usr/lib/gvfs/gvfs-afc-volume-monitor
0  1000  1197  1159  20   0  25144 13764 poll_s S    ?          0:00 /usr/bin/vncserverui -statusicon 7
1  1000  1200     1  20   0   1908   104 wait   S    tty1       0:00 /bin/sh /usr/bin/start-pulseaudio-x11
0  1000  1201  1200  20   0   5792  2040 poll_s S    tty1       0:00 /usr/bin/xprop -root -spy
1  1000  1204     1  20   0  28828  4916 poll_s Ssl  ?          0:00 /usr/lib/menu-cache/menu-cached /tmp/.menu-cached-:0-pi
0  1000  1231     1  20   0  59472  6324 poll_s Sl   ?          0:00 /usr/lib/gvfs/gvfsd-trash --spawner :1.1 /org/gtk/gvfs/exec_spaw/0
1     0  1256     2  20   0      0     0 -      S    ?          0:00 [jbd2/mmcblk0p5-]
1     0  1257     2   0 -20      0     0 -      S<   ?          0:00 [ext4-rsv-conver]
0  1000  1261     1  20   0  45264 17580 poll_s Sl   tty1       0:00 lxterminal
0  1000  1262  1261  20   0   2344  1444 -      S    tty1       0:00 gnome-pty-helper
0  1000  1263  1261  20   0   6376  4520 wait   Ss   pts/0      0:00 /bin/bash
4     0  1277  1263  20   0   6848  3264 -      S+   pts/0      0:00 sudo ./vm205
4     0  1281  1277  20   0 129756 47772 -      Rl+  pts/0      2:52 ./vm205
5     0  1286     1  20   0   3688  1584 -      S+   pts/0      0:00 /usr/bin/dbus-launch --autolaunch 69f85d89fb6f4f42acb1b99eb185f6bf --binary-syntax --close-stderr
1     0  1287     1  20   0   5488  1616 -      Ss   ?          0:00 /usr/bin/dbus-daemon --fork --print-pid 5 --print-address 7 --session
4     0  1296   586  20   0  12144  5140 -      Ss   ?          0:00 sshd: pi [priv]     
5  1000  1302  1296  20   0  12276  3432 -      S    ?          0:00 sshd: pi@pts/1      
0  1000  1304  1302  20   0   6464  4416 wait   Ss   pts/1      0:00 -bash
1     0  1321     2  20   0      0     0 -      S    ?          0:00 [kworker/u8:3]
1     0  1322     2  20   0      0     0 -      S    ?          0:00 [kworker/2:0]
0  1000  1325  1304  20   0   4252  1756 -      R+   pts/1      0:00 ps alx

You are right.
The Raspberry Pi “firmware” is included to the downloads.

In the last link I provided there is written:
"The kernel and firmware are installed as a Debian package, and so will also get updates when using the procedure above. "

.

Hi VEL,

Can I expect a reaction on the details I sent you?
The program still doesn’t work…

Gerard

This is indeed very strange problem.
Thank you for the data you sent.
Still diagnosing the actual root cause of the problem is not an easy task.

I made a test:
I run the program three different ways:
First I typed in the Terminal ./VM205
I got error message but the program started anyway.
In the second test I typed in the Terminal: sudo ./VM205
The program started without any error message.
The third way to start the program without error message was to double click the VM205 in File Manager and select “Execute”.

Hi VEL,

I’m assuming you mean ‘./VM205’ ? Just asking, because my program is called ./vm205’ (lowercase).

In that case, I tried your first and your second option, with a different result for the second one, as I described before.

Gerard

This is strange.
Did you download the program from Velleman VM205 site, the software: “Software package for VM205 with Pascal source code (Rev1.3)”.
In this case it should be VM205 (uppercase)…

Indeed I downloaded it from the Velleman site. Just to be sure: do you have a link for me please?

If memory serves me correctly this is the link I downloaded the package from: https://www.velleman.eu/support/downloads/?code=VM205

But I see that this program has a name in uppercase now… strange…

Also, the directory mine came in was called VM205-master; does that shed any light?

Gerard

Okay, got it. This version does not have the problems I described earlier! (see picture below)
Thanks for your patience VEL.
Apparently I had downloaded another version.

Next question: is there a way I can have the program adapt itself to this screen-size?

Gerard

It seems that there in github.com there is directory VM205-master.
There the software is “vm205” (lowercase), so it seems you have downloaded this version.

I’m happy that your VM205 works now.

I’m sorry, the user interface of the VM205 software doesn’t fit on the screen size of your display.
The minimum vertical number of pixels should be 655.
E.g. resolution 1024x768 will be OK.
There is no (easy) way to resize the user interface.
The only way is to edit the source code and recompile it.

VEL, again, thanks for your patience. I will test it on a bigger monitor tomorrow or Saturday and will keep you posted…

Gerard