TI8148 CAN bus receive

Hi Adrian,

Please use this wiki page for DM814x:  http://processors.wiki.ti.com/index.php/TI81XX_PSP_DCAN_Driver_User_Guide.

BR,

Viet

Hi Viet,

I've seen that page as well: the instructions are exactly the same, and the CAN port doesn't receive.

Adrian

I have used CAN on I8148 EVM under Linux. I have a CAN device connected to dcan0 on the EVM. Here is what I did:   

1. ip link set can0 type can bitrate 50000 <-- CAN device run on this bitrate

2.ip link set can0 up

3. candump can0 &

4. cansend can0 -i 0x4e1 1 2

can0 4E1 [2] 01 02                               <--  recv own message

can0 4E0 [8] 01 02 10 00 C0 00 00 00    <-- recv response message from the CAN device

Hope this helps.

Jiewen

Interesting - I had to change your example slightly, as my CAN device is at 500kBit:

root@dm814x-evm:~# ip link set can0 type can bitrate 500000
root@dm814x-evm:~# ip link set can0 up
d_can d_can: can0: setting CAN BT = 0x504
root@dm814x-evm:~# candump can0 &
root@dm814x-evm:~# interface = can0, family = 29, type = 3, proto = 1
cansend can0 -i 0x4e1 1 2
interface = can0, family = 29, type = 3, proto = 1

My CAN device receives the message transmitted by CAN send, but candump does not see its own message, and does not see the reply message I send from my CAN device. I also get no response trying it at 50kBit/s in loopback mode:

root@dm814x-evm:~# ip link set can0 type can bitrate 50000 loopback on
root@dm814x-evm:~# ip link set can0 up
d_can d_can: can0: setting CAN BT = 0x1c18
root@dm814x-evm:~# candump can0 &
root@dm814x-evm:~# interface = can0, family = 29, type = 3, proto = 1
root@dm814x-evm:~# cansend can0 -i 0x4e1 1 2
interface = can0, family = 29, type = 3, proto = 1

Which SDK / Kernel are you using? This is mine:

root@dm814x-evm:~# cat /proc/version
Linux version 2.6.37 (x0029463@swubn01) (gcc version 4.3.3 (Sourcery G++ Lite 2009q1-203) ) #1 Wed Oct 10 14:02:40 IST 2012

My canutils is the latest from git, and my board stack consists of:

• DM814x/AM387x BASE EVM REV D
• EXPANSION I/O BOARD REV D
• LCD ADAPTER BOARD REV C

Hi Adrian,

Please check the connections details between the EVM and CAN device.

http://processors.wiki.ti.com/index.php/TI81XX_PSP_DCAN_Driver_User_Guide#Connection_details

http://processors.wiki.ti.com/index.php/TI81XX_PSP_DCAN_Driver_User_Guide#Port_details

Once these connections are proper then hardware wise everything fine.

As coming to software:-

1. Can you get the logs for these?

a. dmesg | grep -i can

b. cat /proc/net/can/stats

c. ip -d -s link show can0

2. I hope you have not modified the kernel code (DCAN paltform data, pinmux settings and driver)

3. Can you tell me the PSP/SDK version? (Not the kernel)

4. In loopback mode, we can see both the packets TX & RX.

5. In normal mode we can not see the packets in this board unless other device transmitted.

Regards

AnilKumar

Please mark this Forum post as answered via the Verify Answer button below if it helps answer your question.  Thanks!

The connections appear to be correct (as CAN is a differential bus, the ability to transmit indicates the wiring is fine). I'll get the rest of the logs once I'm back in the office.

Our software versions are ti-ezsdk version 5.05 (5_05_01_04 according to PDF) from Oct 2012 and Linux Kernel: linux-2.6.37-psp04.04.00.01 

To compare further, are you able to run a loopback test on your board (without cable plugged in) and show me the commands and console output so I can replicate?

First of all, 0x4E1 is a message that I used to request response from my CAN device, so the device will send back a 0x4E0 message if it receives 0x4E1. You need to use some

messages that you know your device would recognize. 

Secondly, I think I modified the device drive a bit (in d_can.c), in d_can_poll(), added logic to clear Parity Error status if getting Parity error interrupts.

I did a loopback test, nothing connected to can interface, here is the output:

root@dm814x-evm:~# ip link set can0 type can bitrate 50000 loopback on
root@dm814x-evm:~# ip link set can0 up
d_can d_can.0: can0: resetting d_can ...
d_can d_can.0: can0: setting CAN BT = 0x1c18
root@dm814x-evm:~# candump can0 &
root@dm814x-evm:~# open 0 'can0'.
using interface name 'can0'.

root@dm814x-evm:~# cansend can0 -i 0x4E1 1 1
interface = can0, family = 29, type = 3, proto = 1, idx = 2
new index 0 (can0)
can0 4E1 [2] 01 01
can0 4E1 [2] 01 01
root@dm814x-evm:~# cansend can0 -i 0x1 1 1
interface = can0, family = 29, type = 3, proto = 1, idx = 2
can0 1 [2] 01 01
can0 1 [2] 01 01

Good Luck

Jiewen

Thanks for that - my results are quite different. As you can see, candump does not show any packets:

root@dm814x-evm:~# ip link set can0 type can bitrate 50000 loopback on
root@dm814x-evm:~# ip link set can0 up
d_can d_can: can0: setting CAN BT = 0x1c18
root@dm814x-evm:~# candump can0 &
root@dm814x-evm:~# interface = can0, family = 29, type = 3, proto = 1
cansend can0 -i 0x4E1 1 1
interface = can0, family = 29, type = 3, proto = 1
root@dm814x-evm:~# cansend can0 -i 0x1 1 1
interface = can0, family = 29, type = 3, proto = 1

For Anil Kumar, here are the other logs from the attempt:

root@dm814x-evm:~# cat /proc/net/can/stats

2 transmitted frames (TXF)
0 received frames (RXF)
0 matched frames (RXMF)

0 % total match ratio (RXMR)
0 frames/s total tx rate (TXR)
0 frames/s total rx rate (RXR)

0 % current match ratio (CRXMR)
0 frames/s current tx rate (CTXR)
0 frames/s current rx rate (CRXR)

0 % max match ratio (MRXMR)
1 frames/s max tx rate (MTXR)
0 frames/s max rx rate (MRXR)

1 current receive list entries (CRCV)
2 maximum receive list entries (MRCV)

root@dm814x-evm:~# dmesg | grep -i can
NOR: Can't request GPMC CS
PM: Adding info for platform:d_can
ti81xx_pcie: Starting PCI scan...
CAN device driver interface
CAN bus driver for Bosch D_CAN controller 1.0
PM: Adding info for No Bus:can0
d_can d_can: d_can device registered (irq=52, irq_obj=53)
can: controller area network core (rev 20090105 abi 8)
can: raw protocol (rev 20090105)
can: broadcast manager protocol (rev 20090105 t)
d_can d_can: can0: setting CAN BT = 0x1c18

root@dm814x-evm:~# ip -d -s link show can0
2: can0: <NOARP,UP,LOWER_UP,ECHO> mtu 16 qdisc pfifo_fast state UNKNOWN qlen 10
link/can
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
d_can: tseg1 1..16 tseg2 1..8 sjw 1..4 brp 1..1024 brp-inc 1
clock 20000000
re-started bus-errors arbit-lost error-warn error-pass bus-off
0 0 0 0 0 0
RX: bytes packets errors dropped overrun mcast
0 0 0 0 0 0
TX: bytes packets errors dropped carrier collsns
0 0 0 0 0 0