fdcan.md

How to set up FDCAN on STM32MP157F-DK2 and communicate over Ethernet simultaneously

TUTORIALS

1. https://wiki.st.com/stm32mpu/wiki/How_to_set_up_a_SocketCAN_interface
2. https://wiki.st.com/stm32mpu/wiki/How_to_send_or_receive_CAN_data

TROUBLESHOOTING

If ip link/iplink gives an error like

ip: either "dev" is duplicate, or "type" is garbage

cd ../build-mp1  
bitbake -c menuconfig busybox 

Under Networking Utilities enable iproute and check these websites:

http://www.armadeus.org/wiki/index.php?title=CAN_bus_Linux_driver
https://developer.ridgerun.com/wiki/index.php/How_to_configure_and_use_CAN_bus

0. Activate CAN driver in kernel configuration (enabled by default)

cd ~/Projects/yocto/build-mp1
bitbake -c menuconfig virtual/kernel

[*] Networking support --->
     <*> CAN bus subsystem support --->
             CAN Device Drivers --->
                 <*> Bosch M_CAN support
                     <*> Bosch M_CAN support for io-mapped devices

1. First, install the required stuff

cd ~/Projects/yocto/build-mp1/conf
gedit local.conf

Add the following line to local.conf for sending/receiving CAN data

IMAGE_INSTALL:append = " can-utils"  

Rebuild the image, flash it onto an SD card and boot the system

2. Check the available CAN devices

ls /sys/class/net
ifconfig -a

3. Configure the available SocketCAN interface

ip link set can0 type can bitrate 1000000 dbitrate 2000000 fd on

Print the status of the SocketCAN link

ip -details link show can0

4. Enable the CAN interface and check whether it is up

ip link set can0 up
ip -details link show can0

To disable CAN, run

ip link set can0 down

5. Hardware self-test / Loopback test mode; configure and enable in the same command line

ip link set can0 up type can bitrate 1000000 dbitrate 2000000 fd on loopback on
ip -details link show can0

Send and receive message in internal loopback mode

candump can0 -L &
cansend can0 300#AC.AB.AD.AE.75.49.AD.D1

Ping over Ethernet and send/receive CAN message simultaneously

1. We have been already using the board's terminal on serial port; however we need to set up ssh for also using the terminal over Ethernet. To do so, add the following line to local.conf

cd ~/Projects/yocto/build-mp1/conf

EXTRA_IMAGE_FEATURES ?= "debug-tweaks"
EXTRA_IMAGE_FEATURES += "ssh-server-openssh"  

2. Get the IP address of your board

Board $> ip addr show

3. Connect to your board over Ethernet

PC $> ssh root@<board-ip-address>

4. Ping and test CAN data in two different terminals we set up

Terminal1 $> ping www.google.com

Terminal2 $> ip link set can0 up type can bitrate 1000000 dbitrate 2000000 fd on loopback on
Terminal2 $> ip -details link show can0

Make sure that the CAN link is up

Terminal2 $> candump can0 -L &
Terminal2 $> for counter in {1..20000}; do cansend can0 300#AC.AB.AD.AE.75.49.AD.D1; done