S32KのトピックRe: CAN bit timing

CAN bit timing

ruicui — Wed, 18 Apr 2018 14:04:07 GMT

I am using MBD tool to test CAN speed. From the example "flexcan_can_fd_master_s32k14", it saying 500 kbps(it works, I check it with my CANalyzer). However, I am confused how the parameter were choosen.

1. In the pdf, "RJW is chosen as the smaller of 4 and PHASE_SEG1", then why the following "RJW = 0" can be right?

2. The pdf reference shows different parameter range(1-8):

then the MBD "help" document(0-7):

Thanks,

Ray

Re: CAN bit timing

PetrS — Tue, 24 Apr 2018 07:28:06 GMT

Hi,

it depends if you consider real segment value or programmed value.

Real segment value cannot be zero time quanta long, but the shortest value is 1.

The Programmable value is usually decreased by 1.

So the "fcan_S32K14_config" picture and MBD document shows programmable values for given segments, while the pdf reference shows real segment values.

BR, Petr

Re: CAN bit timing

ruicui — Tue, 24 Apr 2018 12:45:01 GMT

Hello Petr,

I understand that the programmable value is usually decreased by 1. Vector website also have a document to explain it. How about RJW value? in the example, RJW = 0, but "RJW is chosen as the smaller of 4 and PHASE_SEG1".

Thanks,

Rui