HOW-TO MMDVMHost with a DVMega

NOTE: The following is based on a single band RPi shield – it should work with the dual band RPi shield too.  For the Arduino UNO based DVMega, substitute /dev/ttyAMA0 with /dev/ttyACM0.  Also note you should not need to remove getty processes and bootup info from /dev/ttyACM0 as it doesn’t go to them.

FURTHER NOTE: There are slight differences in the processes to remove getty processes between Raspbian Wheezy and Raspbian Jessie – they are annotated along the way.

YET ANOTHER NOTE: You need to disable the built-in bluetooth on a Raspberry Pi 3 to restore UART0/ttyAMA0 over GPIOs 14 & 15 by modifying /boot/config.txt – the process is towards the end just after disabling getty processes on /dev/ttyAMA0.

UPDATE: You can grab the “bleeding edge” source code for MMDVMHost by using G4KLX’s git repository, in which case you don’t need to join the MMDVM Yahoo group and grab the latest release from there.  Instructions at the end …

UPDATE: You can now update the firmware on your DVMega RPi shield directly from the RPi without removing the ATMEGA328 chip or the use of separate cables or Arduinos.  Instructions here.

G0WFV’s Note: Since writing my original post, I have had a change of heart regarding “best practice” when installing MMDVMHost.  You are best off using the bleeding edge code (or at least a labelled release from GitHub) rather than grabbing the files from the group.  The files on Yahoo are now a bit out of date – at the time of writing this note, the file are dated Sep 2016 – considerably old firmware and host software which will be missing a lot of innovations and bug fixes!

Whilst this HOW-TO deals with installing MMDVMHost, the MMDVM firmware can be also grabbed from GitHub – if you do so, ensure you grab matching versions!  Failure to do so can and has lead to unexpected operation of your repeater/hotspot!  Jon tends to label both MMDVMHost and the MMDVM firmware on the same day; look for git commits in MMDVMHost and MMDVM with the comment “Bump the version date” or similar on the same date – these will be matching release versions.

OR (if you are adventurous!) just grab the latest commits of both (they should be compatible with each other!) I have re-written my post to reflect the process I now use to install or update MMDVMHost … 

Install git …

sudo apt-get update
sudo apt-get install git

Grab the source code …

cd ~/Downloads
git clone https://github.com/g4klx/MMDVMHost.git
cd MMDVMHost

If you haven’t already, install make, gcc and other development tools…

sudo apt-get update
sudo apt-get install build-essential

Build MMDVMHost…

cd MMDVMHost
make

Edit MMDVM.ini to suit…

nano MMDVM.ini

Remove the getty process from /dev/ttyAMA0 (Caution: the process is different for Raspbian Wheezy and Raspbian Jessie!)

In Raspbian Wheezy…

nano /etc/inittab

Look for the line that spawns a getty on /dev/ttyAMA0 and comment it out (# at the start of the line).

In Raspbian Jessie…

Stop the getty spawning on /dev/ttyAMA0…

sudo systemctl stop serial-getty@ttyAMA0.service

Prevent it from starting on boot…

sudo systemctl disable serial-getty@ttyAMA0.service

Remove the bootup info from /dev/ttyAMA0 by editing /boot/cmdline.txt and removing references to /dev/ttyAMA0 or serial0 (same process in both Wheezy and Jessie as far as I can tell)…

nano /boot/cmdline.txt

On the Raspberry Pi 3 ONLY, disable built-in Bluetooth…

sudo bash -c 'echo "dtoverlay=pi3-disable-bt" >> /boot/config.txt'

Reboot the Rpi…

sudo reboot

Check group ownership of /dev/ttyAMA0 – it should be dialout and not tty by this stage!  Add yourself to the dialout group…

ls -l /dev/ttyAMA0
crw-rw---T 1 root dialout 204, 64 Mar 10 13:47 /dev/ttyAMA0
sudo usermod –a –G dialout <username>

Logout and log back in.

Change directory back to where you built MMDVMHost and run it…

cd <path>
./MMDVMHost MMDVM.ini