Hello Srinivas Neeli, On 13.01.2022 18:14:06, Srinivas Neeli wrote: > This mail is regarding to understand more on CAN Frame work for CANFD > networks. let's discuss this on the CAN mailing list (Cc'ed). Feel free to subscribe (http://vger.kernel.org/vger-lists.html#linux-can). Please post non HTML mail. > Recently we did few experiments with our CANFD network. Stuff error > observed with different Nominal and Dataphase prescaler configuration > values, which we get from the frame work. > > > For lower baud rates separate prescalers are working good, but when we > switch to high baud rates(like 4Mbps and 5Mbps) observed the BUSOFF > state(Due to stuff errors) on IP(Xilinx). > > With shared prescaler(low prescalers) we are not seeing the issue.. > > In Iso spec also mentioned to avoid tolerance, we have to maintain > common TQ for Nominal and Data phase. > > Spec: ISO 11898-1:2015(E) page no :50 > > " If the same time quantum length is used in the nominal bit time and > in the data bit time and the positions of the sample points in the > nominal bit time are the same in all CAN nodes of a network, then > optimum clock tolerance is accomplished for networks using FD frames." > > CIA: > https://can-newsletter.org/uploads/media/raw/f6a36d1461371a2f86ef0011a513712c.pdf > > From above CAN-newsletter also suggested the same in recommendation 2 and 3. > > Recommendation 2: Set the BRPA bit-rate prescaler equal BRPB > Recommendation 3: Choose BRPA and BRPD as low as possible > > Is there any possibility in framework to use shared prescalars for Nominal and Dataphase?. > > One more question. How to calculate TDCO ?, is there any generic formula for this ?. Marc -- Pengutronix e.K. | Marc Kleine-Budde | Embedded Linux | https://www.pengutronix.de | Vertretung West/Dortmund | Phone: +49-231-2826-924 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
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