MojoLoader RXTXcomm on Fedora linux

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Posts: 3
Joined: January 3rd, 2014, 5:28 pm

MojoLoader RXTXcomm on Fedora linux

Post by johan » January 3rd, 2014, 6:05 pm

Not a question, but might be helpful to others encountering similar issues.

On Fedora the Mojo USB connection is created at port /dev/ttyACM0 (in my case)
In order to access /dev/ttyACM0 the user needs to be part of the 'dialup' group.
This change was not enough to make the loader stay alive when selecting a port.

The MojoLoader distributed in mojo-loader-1.1.2-linux64.tgz tries to create 'lock' files to regulate port usage.
Fedora does not allow lock files to be created at the location that is used.
I tried the following workaround:
- install package rxtx from the repositories
This package is configured to write locks in the appropriate location (performed by native
But unfortunately the java RXTXcomm.jar is programmed only to present /dev/ttyS* devices as available (this is the default behavior of the java code in the RXTX project).

I assume the sources of RXTXcomm.jar where modified to also show /dev/ttyACM* devices.
As a workaround I mixed both distributions and replaced the as delivered in the mojo-loader with the library from the Fedora package.
(overwrite the existing library in mojo/lib with the version in /usr/lib64/rxtx/
This works, but shows a warning about mixing the java code of one version with the native library of the other (smart code).

Hope this helps someone, because it took me a night figuring this one out.

Posts: 7
Joined: October 5th, 2014, 1:34 pm

Re: MojoLoader RXTXcomm on Fedora linux

Post by Tinkerer » October 5th, 2014, 2:08 pm

Thanks! This was just the bit of info I needed!

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