Low speed CAN and Fault Tolerant CAN bus

OLIVIER CÔTÉ 4 years ago in IQANdesign updated by Gustav Widén (System support) 4 years ago 3

We got an issue with standatd automotive components CAN incompatibility. Some devices are on 50kbit/s low speed CAN with fault tolerant tranceivers. We found the way to convert voltage levels in order to reach this standard requirements but IQAN design software limits us on the CAN speed with 100kbit/s value ! WE ABSOLUTLY NEED A SOFTWARE PATCH TO FIX IT otherwise we will have to use a gateway that offer more flexibility than MC4 serie.


The speed 50 kpbs does not work on MC4x. 

In versions 4 and 5, it was possible to select 50 kbps generic CAN for any master, but this speed only worked on the other master modules, it never worked on MC4x. 

In 6.00, the option to select 50 kps was removed from the dropdown list, for both MD4 and MC4x.


47925Remove Generic CAN 50kbit bitrate
Not supported anymore

That's very sad :( These CAN bus are still widely used for low priority communication (HVAC control, speedometer, etc.) on brain new 2020 European vehicles, such as LIN protocol by the way... Is there an actual physical limitation ? Why did you remove this feature ?

Thanks :) 

Yes, the CAN controllers on the MC4 has a limitation that makes 50 kbit/s impossible.

(actually, the physical limitation is only on some of its CAN controllers, but the previous implementation wasn't right for any of them) 

For the normal ISO 11898-2 high speed CAN, 50 kbit/s seems to be quite unusual. I am only aware of two IQAN application where it was used.