PB2 CANbus testing

General Discussion
1

PB2 CANbus
added k3-am62x-sk-mcan.dtbo to extlinux.conf

ip link shows all three CAN present

3: can0: <NOARP,ECHO> mtu 16 qdisc noop state DOWN mode DEFAULT group default qlen 10
    link/can 
4: can1: <NOARP,ECHO> mtu 16 qdisc noop state DOWN mode DEFAULT group default qlen 10
    link/can 
5: can2: <NOARP,ECHO> mtu 16 qdisc noop state DOWN mode DEFAULT group default qlen 10
    link/can 


have two BBBlue with CAN working
tapped into the CANbus wire to connect the PB2 via a SN65HVD230 CAN Bus Transceiver (edit, the 120 ohm resistor was removed on this module)
i'm getting rx data on the CRX pin of the transceiver, but no out put on the terminal
also, if i run "sudo cangen can0" from PB2 there is no data on CTX pin of the transceiver

BBBlue (Bookworm IoT Image 2023-10-07)
sudo cangen can0

PB2 (Bookworm Minimal Image 2025-06-30)
sudo candump can0

any thoughts as to what i'm missing??
1 Like
2

@amf99 I have no idea what you are missing.

I am interested in which pins you have determined give you CAN_TXD and CAN_RXD? I think from the documentation, the best ones are P2.05 and P2.07.

I also need an I2C bus. Since I prefer to only jumper from our board to the one header on the PB2, I am looking at using I2C3 which is P2_11 and P2_09. The only thing that isn’t on P2 is +5 in but I can live with that.

I’m designing a PCB that I want to be able to work with a Black, Green or a PocketBeagle so getting this right now is important of course.

1 Like
3

being all three CAN showed after loading the dtbo,

per the documentation, these pins should work. i’m planing on testing all three.

i’m still trying to get it to work. but will post when it is working.

MCU_MCAN0
    P1.26A, TX, M0
    P1.28A, RX, M0
MCAN0   
    P2.05, TX, M0
    P2.07, RX, M0
MCU_MCAN1
    P2.09A, RX, M0
    P2.11A, TX, M0
2 Likes
4

Thanks. Ultimately, I plan for the PocketBeagle2 to boot, start our program and get all its communications and instructions over CANbus from the main ECU. This way we won’t have to try to add a wifi or BT capability.

5

first CAN does work on all three busses, just have to match up the 0,1,2 with the correct pins.

'```

Bookworm Minimal Image 2025-06-30
MCAN0 >> CAN1
MCU_MCAN1 >> CAN0
MCU_MCAN0 >> CAN2

6

I also performed the operations as you did, but in loopback mode, I can receive data, while in normal mode, it doesn’t work. I used an oscilloscope to capture the waveform of the PocketBeagle2’s pins, and there was no change at all. Can your CAN normal mode send and receive? I am using a CAN transceiver model JTA1051.

7

i’m not an expert in CAN bus,

not sure there is a loop back mode, the following link also indicates this.

now i think you can use two CANs on the same board to talk to each other, but with transceivers. haven’t tried this, but it should work

1 Like