Connecting OPP to your computer

Connect the OPP board to your computer via USB. Make sure that your OPP chains do not get too long since the serial throughput is limited per chain. You can connect multiple chains.

On Linux: Blacklist cytherm module

If you are using OPP hardware on linux you should blacklist the cypress thermometer because it conflicts with OPP.

In /etc/modprobe.d/blacklist.conf add:

blacklist cytherm

If blacklist.conf does not exist, just create a new empty file as root. Afterwards, reboot your PC.

On Linux: Add udev rules to ensure persistent device names

If you have more than one ttyACM connected to your PC (e.g. multiple OPP chains or other USB-serial adapters) you can assign a name to your ports based on the USB port they are connected to.

First identify the port of your OPP hardware. Usually it should be /dev/ttyACM0 or /dev/ttyACM1.

Then run udevadm info on your port:

udevadm info /dev/ttyACM0

This will show you the DEVPATH. Now replace the last part ttyACMX with an asterisk and add an udev rules like this in /etc/udev/rules.d/opp.rules:

SUBSYSTEM=="tty", ACTION=="add", DEVPATH=="/devices/pci0000:00/0000:00:14.0/usb1/1-4/1-4:1.1/*", SYMLINK+="ttyOPP1", GROUP="adm", MODE="0660"

After a reboot you should get a /dev/ttyOPP1 device if you connect an OPP device to that specific USB port. You can use that port in your config.

On Ubuntu: Stop ModemManager

ModemManager tries to initialise all /dev/ttyACMxx devices as modem. That might cause delays after attaching OPP hardware and might also leave the hardware in a weird state with garbage on the bus. If you do not use any modems just disable and stop ModemManager:

sudo systemctl disable ModemManager
sudo systemctl stop ModemManager