At Sun, 21 Jul 2019 18:38:10 -0700 (PDT) [email protected] wrote:
> > > > > Kernel version: 4.19.31-ti-r19 > OS: Ubuntu 18.04.2 LTS > BB Board: Beaglebone Black Enhanced (Sancloud) > > Hello, > > I am trying to use P9_24 and P9_26 for CAN (controller area network). The > following are the steps I am taking to enable the pins and attempt to send > messages over CAN: > > config-pin P9_24 can > config-pin P9_26 can > sudo ip link set can0 up type can bitrate 500000 > sudo ifconfig can0 up I think you need can1 here, not can0. *I* got things to work with my LCC CAN Cape board (https://www.pcbway.com/project/shareproject/LCC_CAN_Cape_for_Beagle_Bone_Black.html). I have its eeprom set to load /lib/firmware/BB-CAN1-00A0.dtbo at boot time, I can then configure can1 and it works just fine. I think BB-CAN1-00A0.dtbo does a little more than merely what config-pin does. I'd suggest editint /boot/uEnv.txt to load the BB-CAN1-00A0 overlay and then configuring can1... > cangen can0 -i -g 100 -v > > cangen shows that it is generating messages, but when I view the voltage > levels of P9_24 and P9_26 under and oscilloscope, there is no change in > voltage. The voltage remains at 3.1V-3.2V. > > When I query the pins, the configuration is correct: > > config-pin -q P9_24 > P9_24 Mode: can > config-pin -q P9_26 > P9_26 Mode: can > > > If I change the pin configuration to "gpio" for example, I can see a > voltage change in the oscilloscope for both pins accordingly. I have tried > to configure P9_19 and P9_20 for CAN as well and I have the same results. > > Does anyone have any idea tips on how to get the BB to send CAN messages? > Do I need to configure anything else before it works? > > (I do have a CAN transceiver which will interface on the CAN bus, but I was > not able to see messages from the BB on the CAN bus, which lead me to debug > the voltage at the BB I/O pins first before debugging it over to the > transceiver. It appears my issue is that the BB pins are not transmitting > anything currently.) > > Thanks for the help! > -- Robert Heller -- 978-544-6933 Deepwoods Software -- Custom Software Services http://www.deepsoft.com/ -- Linux Administration Services [email protected] -- Webhosting Services -- 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/20190722144027.E0AB526C0173%40sharky3.deepsoft.com.
