Internal resistor in CAN bus shield v2.0

Products & Technology Arduino & Seeeduino
#1

Hi.



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.



//Nasser

#2

Hi Nasser,



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





Seeed techsupport team

Bill

#3

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.

#4

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