On Fri, 14 May 2021 12:04:47 +0000, Patrick Menschel wrote: > Hi Kurt, > > J1939 just hit the raspberrypi-kernel-headers and will soon be part of > regular raspberrypi-kernel [1] while it was already > available in Python 3.9 for a couple of month. [2] > > I was about to give it a spin but was confused of the call parameters. > > Could you shed some light on the intended usage. > > Do I need to open one socket per PGN I'm sending? > e.g. > > s1 = socket.socket(socket.AF_CAN, socket.SOCK_DGRAM, socket.CAN_J1939) > s1.bind(interface_name, MY_NAME, PGN_OF_TSC1, MY_SA) > s1.write(bytes(8)) > > s2 = socket.socket(socket.AF_CAN, socket.SOCK_DGRAM, socket.CAN_J1939) > s2.bind(interface_name, MY_NAME, PGN_OF_EBC1, MY_SA) > s2.write(bytes(8)) No, you don't _need_ to. You can. If you need quite some different PGN's, it may be more interesting to: s = socket.socket(socket.AF_CAN, socket.SOCK_DGRAM, socket.CAN_J1939) s.bind(interface_name, MY_NAME, ANY_PGN, MY_SA) s.sendto(bytes(8), DST_1, PGN_1) s.sendto(bytes(8), DST_2, PGN_2) ... I'm not a python expert, I just assume something like that is possible. > > > What about the cyclic transmitted PGNs? Do I drop those into > BroadcastManager somehow? The broadcast manager is seperate from j1939, so it's apart. > > > If I want to open an ISOTP Channel while a j1939 socket exists for my > SA, does anything weird happen on that socket? No, nothing weird will happen. The only possible disadvantage I can think of is that the messages sent using ISOTP do not honor the NAME-SA mapping, so on a bus with dynamic addressing, you should be carefull to use local/remote addresses. Kind regards, Kurt
