Hi everyone!
I'm here with my devkit and trying to have FDCAN working properly! I compiled the Yocto distribution for the board and I followed all the tutorials in the wiki ( https://wiki.st.com/stm32mpu/wiki/Category:CAN ) and here's what I came up with:
I initialized m_can1
&m_can1 {
pinctrl-names = "default", "sleep";
pinctrl-0 = <&m_can1_pins_b>;
pinctrl-1 = <&m_can1_sleep_pins_b>;
status = "okay";
};
I used the pins_b configuration because looking at the datasheet they were the only possible exposed pins on the PI_GPIO extender (CN2) on the board (overwriting I2C5 pins for the Arduino). I also removed the pullup resistors for i2c (R166 and R167).
On the kernel side I tried the loopback and seems to work fine:
root@stm32mp1:~# ip link set can0 up type can bitrate 1000000 dbitrate 2000000 fd on
[ 1602.982564] m_can_platform 4400e000.can can0: bitrate error 0.3%
[ 1602.988958] m_can_platform 4400e000.can can0: bitrate error 0.3%
[ 1602.994593] IPv6: ADDRCONF(NETDEV_CHANGE): can0: link becomes ready
(the second bitrate error is different from the tutorials...) and seems working ok
root@stm32mp1:~# candump can0 -L &
root@stm32mp1:~# cansend can0 300#AC.AB.AD.AE.75.49.AD.D1
(1669130989.509567) can0 300#ACABADAE7549ADD1
(1669130989.509533) can0 300#ACABADAE7549ADD1
Now, I'm trying to get some data on the physical bus but it seems not working, I attached the oscilloscope on the pin PA12 (EXP_GPIO2) which should be the FDCAN tx, and enabled the bus as the example :
ip link set can0 up type can bitrate 1000000 dbitrate 2000000 fd on
But I can see absolutely nothing on the pin if I send any packet with cansend.
I also tried to attach a proper transceiver ( I used mikro CAN FD 3 click https://www.mikroe.com/can-fd-3-click --> TLE9251V based) , and after the cansend, the bus goes instantly bus-off :
root@stm32mp1:~# cansend can0 01a#11223344AABBCCFF
[ 706.810510] m_can_platform 4400e000.can can0: bus-off
Do you have any suggestions to make the protocol work properly? Do you have tried it yourself?
Huge thanks!
Simone
