Setting up P1 and sending/reading CAN messages.
This page shows how to set up P1 and interface with your car's OBD port.
- P1 (consists of PocketBeagle, Adapter board and Interface board) Note: the Interface board is same as used on M2.
The following parts are common and can be found from many sources/manufacturers.
The adapter board plugs directly into the M2 Interface board and provides:
1. Routing of power and signals from M2 Interface board to PocketBeagle.
2. Battery connector for standard 2-Pin JST battery connector and single cell lithium battery. (Optional)
3. USB A host port with ESD protection.
4. Voltage scaling for 6 Analog inputs.
5. Several 0 ohm jumpers to route signals as needed.
Adapter PCB files are found at these links:
The adapter PCB is pre-installed onto the M2 interface board. The PocketBeagle is also pre-installed onto the adapter board. Since the PocketBeagle is not keyed, if you remove, be sure to plug it in so that the USB ports are on the same side.
A USB wireless adapter can be plugged directly into the board, no powered USB hub required.
Note: The P1 kit ships with pre-installed image on SD card!
Plug a microUSB cable into the PocketBeagle and your computer. After a minute or so, use your favorite terminal to ssh to beagle.local or 192.168.7.2:
Login: debian Password: temppwd
We want to make sure that others wont be able to access your device to do this the main thing we are going to do is change the root password.
sudo passwd root
First thing we'll want to do is connect to the internet to be able to download the latest packages. To do that, we'll use WIFI. Type the commands as shown below
connmanctl> disable wifi
connmanctl> enable wifi
connmanctl> scan wifi
Scan completed for wifi
All of the hotspots that your setup can see will be listed here, and look something like this:
Run these commands to connect:
connmanctl> agent on
connmanctl> connect wifi_xxxxxx_xxxxxx_managed_psk
You should now be connected to your local WiFi. You can check that you have an IP address by typing the following in the terminal window:
You should now see an IP address under wlan0 and you can now connect to this IP address in the future to program your PocketBeagle.
If you have trouble with the WiFi connection after initial setup, then ssh over the USB cable to the BeagleBone and run:
sudo connmanctl disable wifi
sudo connmanctl enable wifi
After connecting to internet, we can update the PocketBeagle by running these two commands, this should take a few minutes.
sudo apt update
sudo apt upgrade
Next we make sure the pins on the PocketBeagle are set up correctly as shown at this link:
The following steps only need to be performed once. The correct pin configuration will then persist across reboots. Verify that that these files exist:
ls -lt /lib/firmware/PB-CAN0-00A0.dtbo
ls -la /lib/firmware/PB-CAN1-00A0.dtbo
Edit the boot configuration so the CAN0 and CAN1 pins will be configured automatically:
sudo nano /boot/uEnv.txt
replace these lines:
with these lines:
save the file (ctrl-o) and exit (ctrl-x) and then reboot:
Next, we set up the CAN interface and turn it on. Note that we are setting rate at 250Kb/s here. Your car might be a different BAUD rate.
P1 is now set up! Step 6 and beyond are for testing and becoming more familiar with CAN on P1, try them if you'd like, or check out the P1 Mini-Projects.
sudo ip link set can0 type can bitrate 250000 listen-only on
sudo ifconfig can0 up
To see actual data, we need to do 2 things: 1. Plug M2/PocketBeagle into your car or an emulator (No need for hub, and WIFI dongle anymore - those can be unplugged) and 2. enter this command to print output to terminal screen:
candump -cae can0,0:0,#FFFFFFFF
If everything is set up correctly, you should see something like this:
While this looks pretty cool, it is hard to see what is going on. Press CTRL+C to end output to terminal.
Logging CAN data to a file makes it easier to analyze the data. To do that, use this command to log data to current working directory:
candump -l any,0:0,#FFFFFFFF
Run these commands to enable the CAN1 interface and print anything received to the terminal:
sudo ip link set can1 type can bitrate 250000 listen-only on
sudo ifconfig can1 up
candump -cae can1,0:0,#FFFFFFFF
This should be used for testing purposes only and caution should be taken before sending messages to a real car. Here are instructions on how to send CAN messages on the CAN0 interface.
sudo ip link set can0 type can bitrate 250000
sudo ip link set up can0
cansend can0 01a#11223344AABBCCDD
You can test sending and receiving CAN a couple ways:
- Use two sets of P1 and the OBD3way and 12V power supply.