CAN1 does not work BBB

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1

Hello,
I have a problem with the CAN1 interface on my Beaglebone Black.

debian@beaglebone:~$ sudo /opt/scripts/tools/version.sh
[sudo] password for debian:
git:/opt/scripts/:[8f20cac93cbbec2ab705333a543903287ff9e7d4]
eeprom:[A335BNLT00C02017BBBK05D5]
model:[TI_AM335x_BeagleBone_Black]
dogtag:[BeagleBoard.org Debian Image 2018-10-07]
bootloader:[microSD-(push-button)]:[/dev/mmcblk0]:[U-Boot 2019.04-00002-gbb4af0f 50f]:[location: dd MBR]
bootloader:[eMMC-(default)]:[/dev/mmcblk1]:[U-Boot 2019.04-00002-gbb4af0f50f]:[l ocation: dd MBR]
UBOOT: Booted Device-Tree:[am335x-boneblack-uboot-univ.dts]
UBOOT: Loaded Overlay:[AM335X-PRU-RPROC-4-14-TI-00A0]
UBOOT: Loaded Overlay:[BB-ADC-00A0]
UBOOT: Loaded Overlay:[BB-BONE-eMMC1-01-00A0]
UBOOT: Loaded Overlay:[BB-CAN1-00A0]
UBOOT: Loaded Overlay:[BB-I2C2-00A0]
UBOOT: Loaded Overlay:[BB-NHDMI-TDA998x-00A0]
UBOOT: Loaded Overlay:[BB-SPIDEV0-00A0]
kernel:[4.14.108-ti-r118]
nodejs:[v6.17.0]
/boot/uEnv.txt Settings:
uboot_overlay_options:[enable_uboot_overlays=1]
uboot_overlay_options:[uboot_overlay_addr4=/lib/firmware/BB-SPIDEV0-00A0.dtbo]
uboot_overlay_options:[uboot_overlay_addr5=/lib/firmware/BB-I2C2-00A0.dtbo]
uboot_overlay_options:[uboot_overlay_addr6=/lib/firmware/BB-CAN1-00A0.dtbo]
uboot_overlay_options:[disable_uboot_overlay_audio=1]
uboot_overlay_options:[disable_uboot_overlay_wireless=1]
uboot_overlay_options:[uboot_overlay_pru=/lib/firmware/AM335X-PRU-RPROC-4-14-TI- 00A0.dtbo]
uboot_overlay_options:[enable_uboot_cape_universal=1]
pkg check: to individually upgrade run: [sudo apt install --only-upgrade ]
pkg:[bb-cape-overlays]:[4.4.20190922.0-0rcnee0~stretch+20190922]
pkg:[bb-wl18xx-firmware]:[1.20190227.1-0rcnee0~stretch+20190227]
pkg:[kmod]:[23-2rcnee1~stretch+20171005]
pkg:[librobotcontrol]:[1.0.4-git20190227.1-0rcnee0~stretch+20190327]
pkg:[firmware-ti-connectivity]:[20180825+dfsg-1rcnee1~stretch+20181217]
groups:[debian : debian adm kmem dialout cdrom floppy audio dip video plugdev us ers systemd-journal i2c bluetooth netdev cloud9ide gpio pwm eqep admin spi tisdk weston-launch xenomai autologin]
cmdline:[console=ttyO0,115200n8 bone_capemgr.uboot_capemgr_enabled=1 root=/dev/m mcblk0p1 ro rootfstype=ext4 rootwait coherent_pool=1M net.ifnames=0 quiet]
dmesg | grep remote
[ 1.244859] remoteproc remoteproc0: wkup_m3 is available
[ 1.464098] remoteproc remoteproc0: powering up wkup_m3
[ 1.464219] remoteproc remoteproc0: Booting fw image am335x-pm-firmware.elf, size 217168
[ 1.468443] remoteproc remoteproc0: remote processor wkup_m3 is now up
[ 10.159438] remoteproc remoteproc1: 4a334000.pru is available
[ 10.179638] remoteproc remoteproc2: 4a338000.pru is available
dmesg | grep pru
[ 10.135980] pruss 4a300000.pruss: creating PRU cores and other child platform devices
[ 10.159438] remoteproc remoteproc1: 4a334000.pru is available
[ 10.159565] pru-rproc 4a334000.pru: PRU rproc node /ocp/pruss_soc_bus@4a32600 4/pruss@0/pru@34000 probed successfully
[ 10.179638] remoteproc remoteproc2: 4a338000.pru is available
[ 10.179757] pru-rproc 4a338000.pru: PRU rproc node /ocp/pruss_soc_bus@4a32600 4/pruss@0/pru@38000 probed successfully
dmesg | grep pinctrl-single
[ 0.943534] pinctrl-single 44e10800.pinmux: 142 pins at pa f9e10800 size 568
dmesg | grep gpio-of-helper
[ 0.955505] gpio-of-helper ocp:cape-universal: ready
lsusb
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
END

debian@beaglebone:~$ cat /sys/kernel/debug/pinctrl/44e10800.pinmux/pinmux-pins

…

pin 96 (PIN96): 481d0000.can (GPIO UNCLAIMED) function pinmux_dcan1_pins group pinmux_dcan1_pins
pin 97 (PIN97): 481d0000.can (GPIO UNCLAIMED) function pinmux_dcan1_pins group pinmux_dcan1_pins

…

debian@beaglebone:~$ sudo ip link set can1 up type can bitrate 125000

everythings fine with no Error or Warning.

and then i try:
debian@beaglebone:~$ cansend can1 07f#4004

Nothing happens at the CAN bus

debian@beaglebone:~$ cansend can1 07f#4004
debian@beaglebone:~$ cansend can1 07f#4004
debian@beaglebone:~$ cansend can1 07f#4004
debian@beaglebone:~$ cansend can1 07f#4004
debian@beaglebone:~$ cansend can1 07f#4004
debian@beaglebone:~$ ip -details -statistics link show can1
3: can1: <NO-CARRIER,NOARP,UP,ECHO> mtu 16 qdisc pfifo_fast state DOWN mode DEFAULT group default qlen 10
link/can promiscuity 0
can state BUS-OFF (berr-counter tx 248 rx 0) restart-ms 0
bitrate 125000 sample-point 0.875
tq 500 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
re-started bus-errors arbit-lost error-warn error-pass bus-off
0 0 0 1 1 1 numtxque ues 1 numrxqueues 1 gso_max_size 65536 gso_max_segs 65535
RX: bytes packets errors dropped overrun mcast
24 3 0 0 0 0
TX: bytes packets errors dropped carrier collsns
0 0 0 0 0 0
debian@beaglebone:~$

What am I doing wrong? Why is nothing transmitted ?
I monitored the output with an oscilloscope.

And another problem.
Due to the problems with the CAN bus I tried to make a kernel and boatloader update.
But I get the following error message.

debian@beaglebone:/opt/scripts/tools$ git pull
fatal: unable to access ‘https://github.com/RobertCNelson/boot-scripts/’: server certificate verification failed. CAfile: /etc/ssl/certs/ca-certificates.crt CRLfile: none
debian@beaglebone:/opt/scripts/tools$

many thanks in advance and have a nice day @ all

2

Did you try using config-pin instead of the overlay?

See my post regarding a similar issue i had and see if it helps you:
https://groups.google.com/forum/#!msg/beagleboard/uCzaLNgAJks/-4OJkhgDBgAJ

3

What CAN transceiver are you using? Have you verified your transceiver works?

4

I tried it with overlays and with config-pin.
But both did not work.
We check the pins directly on the Board.

5

What CAN transceiver are you using? Have you verified your transceiver works?

6

Hi,
I do not have one connected right now.
I am watching pin9-24 and pin9-26 with an oscilloscope. And nothing happens there.
Best regards

7

CAN doesn’t work without at least two nodes on the bus in order to ACK messages. You can see that your can1 device went into BUS-OFF. However, you should see the first attempts to send a package until the device had too many unacknowledged retries.

For what it’s worth, I am using CAN without issues on the BBB with the same CAN1 overlay but I am initializing and using can0 instead of can1, maybe that’s worth a try.

8

Like Bert said, you need two devices AND a transceiver. I hope you did not try to connect the BB straight into the CAN bus without a transceiver!

9

Like Bert said, you need two devices AND a transceiver.
Yes, and the other receiver has to be correctly set up with the same speed. When This is wrong, the pins P9.24 and P9.26 are not outputting data.
The hardware is needed to make it work.

10

Thanks again to everyone,
The problem was the transceiver.
Current I work with the original Cape and ist works fine.