Am 21.10.2010 14:28, schrieb Marc Kleine-Budde: > Moin, > > the socket CAN implementation allows sending of CAN frames with RTR set > and dlc != 0. My question is what should be received? > > I've tested several CAN cores (sja1000, mcp2515, at91_can) and all > receive the RTR bit and set the dlc correct, but the data is not handled > as expected. On the at91 and mcp2515 it seems that we get the old > mailbox data, on the sja1000 we get the old data but shifted by several > bytes. > > Our options are: > leave as it is, or combinations of these: > > 1) drop frames with RTR && dlc != 0 > 2) set dlc = 0 if RTR is set > 3) set data = to 0 if RTR is set > > a) during RX > b) during TX > > cheers, Marc > > > > _______________________________________________ > Socketcan-core mailing list > [email protected] > https://lists.berlios.de/mailman/listinfo/socketcan-core Hello,
AFAIK a RTR frame is intended to request a frame with the length as set in the DLC of the RTR frame. So it should be no problem to send a frame with DLC!=0 and RTR set. For a received message the data content is invalid, but dlc is. I think the application should handle this. This leads to option 3) Regards Gerhard -- EMS Dr. Thomas Wuensche e.K. Sonnenhang 3 85304 Ilmmuenster HRA Neuburg a.d. Donau, HR-Nr. 70.106 Phone: +49-8441-490260 Fax : +49-8441-81860 http://www.ems-wuensche.com _______________________________________________ Socketcan-core mailing list [email protected] https://lists.berlios.de/mailman/listinfo/socketcan-core
