Software Selectable CAN Termination in S32K344

[ganavi1]

I am using FRDM-A-S32K344 with RTD 3.0.0.

I want to know whether CAN termination resistor can be enabled or disabled through software in S32K344.

Does S32K344 support this internally, or do we need external hardware control 

Also, could you please explain how CAN termination is normally designed between the MCU and CAN transceiver, and how software-controlled CAN termination can be implemented?

[PetrS]

Hi,

there is no direct support for software‑selectable CAN termination in S32K3 MCUs or in our standard CAN transceivers.

The typical connection is: MCU (FlexCAN TX/RX) ↔ CAN transceiver ↔ CANH/CANL bus, with termination resistor(s) placed on the bus side.

Standard high‑speed CAN/CAN FD requires two 120 Ω resistors (or split termination: 2×60 Ω with a capacitor to ground), located at each end of the bus backbone. Each ECU node in between are usually not terminated.

If software‑selectable termination is required, it must be implemented using external hardware, typically a GPIO‑controlled analog switch, FET, or relay that inserts or removes the termination resistor.

BR, Petr

[ganavi1]

Thanks for your reply