<https://lh3.googleusercontent.com/-Xowo6dsQ8uk/WUtjgjYJmsI/AAAAAAAAAZc/hFPTgyv5f2INLpL7L9jlXxUedNpLmJ6wACLcBGAs/s1600/%25E7%2594%25B5%25E8%25B7%25AF1.png> <https://lh3.googleusercontent.com/-TQUmBQ2tJEw/WUtjYB3ZYDI/AAAAAAAAAZY/oEn8wrnXWdU8ifMJMB3DsXIsp76b6AYNQCLcBGAs/s1600/%25E7%2594%25B5%25E8%25B7%25AF.png>
I use a TJA1050 module to expand My beaglebone black.The two picture up is my circuit. I use two resistors（10K and 4.7K） to convert 5V to 3.3V. Now，the problem is that when I set can0 up , It could only run on lookback mode, I can get CAN message use (candump can0). It doesn't work on other mode. I can get nothing. I work with this reference (https://docs.google.com/document/d/1sgurQ-7gLyn7g-Kg983NRM0aDkYEqHqy9dmrieX_RUM/edit#) DCAN1_RX P9_24 serial in from CAN bus -27 - +40V common-mode voltage on bus DCAN1_TX P9_26 serial out to CAN bus 3V max driver differential output voltage pin used. I use USB-CAN adapter to test. <https://lh3.googleusercontent.com/-sXcnPTJMaOI/WUtmvqYfCaI/AAAAAAAAAZo/SqeukMAuQ-4GgI9RPSfMRIZsJE6YcnACACLcBGAs/s1600/wave.png> I get this from DCAN1_RX pin. So I think the wiring of CAN bus is fine. I think there is noly two possibilities. Frist there is some thing wrong with my work. And The second , My BBB is broken. There is more info below. debian@beaglebone:~$ sudo ip link set can0 type can bitrate 50000 loopback on debian@beaglebone:~$ ip -details link show can0 5: can0: <NOARP,ECHO> mtu 16 qdisc pfifo_fast state DOWN mode DEFAULT group default qlen 10 link/can promiscuity 0 can <LOOPBACK> state STOPPED (berr-counter tx 0 rx 0) restart-ms 0 bitrate 50000 sample-point 0.875 tq 1250 prop-seg 6 phase-seg1 7 phase-seg2 2 sjw 1 c_can: tseg1 2..16 tseg2 1..8 sjw 1..4 brp 1..1024 brp-inc 1 clock 24000000 debian@beaglebone:~$ sudo ifconfig can0 up debian@beaglebone:~$ ip -details link show can0 5: can0: <NOARP,UP,LOWER_UP,ECHO> mtu 16 qdisc pfifo_fast state UNKNOWN mode DEFAULT group default qlen 10 link/can promiscuity 0 can <LOOPBACK> state ERROR-ACTIVE (berr-counter tx 0 rx 0) restart-ms 0 bitrate 50000 sample-point 0.875 tq 1250 prop-seg 6 phase-seg1 7 phase-seg2 2 sjw 1 c_can: tseg1 2..16 tseg2 1..8 sjw 1..4 brp 1..1024 brp-inc 1 clock 24000000 debian@beaglebone:~$ candump can0 can0 123 [8] 00 01 02 03 04 05 06 07 can0 123 [8] 00 01 02 03 04 05 06 07 can0 123 [8] 00 01 02 03 04 05 06 08 can0 123 [8] 00 01 02 03 04 05 06 08 debian@beaglebone:~$ ifconfig can0 Link encap:UNSPEC HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 UP RUNNING NOARP MTU:16 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:10 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) Interrupt:208 -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/805242c4-b0df-4b75-b580-2c71b35271bb%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
