Internal resistor in CAN bus shield v2.0


I just bought a CAN bus shield v2.0. The instruction manual clearly explains how to connect two CAN nodes, but I need to have 3 nodes in my setup and I am wondering if I need to add resistors manually. A CAN bus requires 120 Ohm termination resistors at each end of the bus. Do Seeed-studio CAN bus shields have built in termination resistors? What about connecting my setup to an existing CAN bus, e.g. a real car CAN bus, that already has termination resistors?

I would appreciate if someone shed some light on the matter.


Hi Nasser,

We add 120ohm resistor between CAN_H and CAN_L. Please refer to below schematic. thanks.

Seeed techsupport team


Hello Bill,

Thanks for your support. Then it means I don’t need to manually add 120 ohm resistors between multiple Seeed-studio CAN shields.

However, I am still confused about connecting my CAN shield to an existing CAN bus such as my car (that already has 120 ohm resistor). Should I turn off the internal resistor on my CAN shield? and if yes, how?

Thanks in advance.

Hi Nasser, you can cut the P1 on backside of CAN bus shield. thanks.