DS213 Web Oscilloscope application gives no data (Hard Fault)

[Martyx00]

Hi,
I have successfully installed the latest build for the DS213 (https://github.com/gabonator/LA104/releases/tag/2020.12.23). However, I cant make the Web Oscilloscope to work. When I select the app upon the boot and connect the device to computer, I get the pop-up which opens the application, but than nothing happens, no data appear.
The device is registered under /dev/ttyACM1. I am using Ubuntu 22.10, are there any tricks that I have to do to make it work?

[28737.107080] usb 1-2: new full-speed USB device number 23 using xhci_hcd
[28737.287040] usb 1-2: New USB device found, idVendor=1209, idProduct=db42, bcdDevice= 2.20
[28737.287052] usb 1-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[28737.287056] usb 1-2: Product: DS203 Oscilloscope
[28737.287059] usb 1-2: Manufacturer: Gabriel
[28737.287062] usb 1-2: SerialNumber: 037302574241303939FFD70
[28737.341270] cdc_acm 1-2:1.0: ttyACM1: USB ACM device

[Martyx00]

Sending any character via serial causes Hard Fault and register dump on the screen.

[gabonator]

Try this
webosc213.zip

[Martyx00]

The issue is the same (except that the PC during the crash is now at 0x80644D0).

[gabonator]

I have just tried it and everything works well - at least on OSX. Make sure you have following page opened: https://rawgit.valky.eu/gabonator/LA104/master/system/apps_featured/69_webusbosc/web/v3/index.html

But I confirm that it crashes when I send a single character through serial link with
screen /dev/tty.usbmodem101 9600
as well as with
minicom -D /dev/tty.usbmodem101

This is a bit strange and I will investigate this issue following days

[Martyx00]

Just made it work, I had to add permissions for USB control to my current user:

echo 'SUBSYSTEM=="usb", MODE="0660", GROUP="plugdev"' > /etc/udev/rules.d/00-usb-permissions.rules
udevadm control --reload-rules

Than just add the user into the plugdev group and it should work.

[gabonator]

Found the bug, fixed here: 5ecea19

Unfortunately it is not possible to verify the remote procedure call interface with minicom. Every packet sent over USB is processed as a single command. There was a bug when the RPC did not expect unterminated messages to be received and sending single character caused a null pointer dereferencing. There is an easy trick how to test the RPC interface from command line:

echo 'DBG::Print("Hello!");' > /dev/cu.usbmodem1101
echo 'LCD::Bar(CRect(20, 20, 300, 150), 0xaaaa);' > /dev/cu.usbmodem1101
echo 'LCD::Print(50, 80, 0xffff, 0xaaaa, "Hello world!");' > /dev/cu.usbmodem1101

(in OSX redirecting to /dev/tty.usbmodem1101 did not work)

Thank you very much for reporting this issue and for the permissions hack

This is fixed app which should not crash (in worst case it should only freeze with assertion message)
69webos1.zip