BARTH STG-850 Support

[ben-mcdonnell-hacksmith]

BARTH STG-850 Support

[nopnop2002]

I am not sure what the internal CAN transceiver is

You need to clarify the transceiver you are using.

[ben-mcdonnell-hacksmith]

They aren't super forthcoming with details, but from some Keil example code, it appears to be a sn65hvd234 transceiver.

[nopnop2002]

with a BARTH STG-850

The stm32f072 sample is for STM32F0 running at 48MHz.

This board needs to run at 48MHz.

Transmission failures have been reported many times in the past.

Everything is due to physical causes.

https://github.com/nopnop2002/Arduino-STM32-CAN/issues/

If the transmission fails, these are the possible causes.

• There is no receiving app on CanBus.
• The speed does not match the receiver.
• There is no terminating resistor on the CanBus.
• There are three terminating resistors on the CanBus.
• The resistance value of the terminating resistor is incorrect.
• 3.3V transceiver and 5V transceiver are mixed.
  +1V Ground Shift using Split Termination.
  Check here.
• Stub length in CAN bus is too long.
  Though the ISO11898 Standard specifies a maximum bus length of 40m and maximum stub length of 0.3m at 1Mbps.
  See here.
• Noise effects.
  It occurs when the wire cable is thin or wire cable is crossing.
  It is preferable to use wires that are noise-proof.

I changed the single wire to twisted wire. It's fixed.

You will probably need to open the case and check the XTAL used, presence or absence of a terminating resistor, transceiver model number, and internal wiring using a multimeter .

[ben-mcdonnell-hacksmith]

The board isn't running at 48mhz, according to the datasheet it is running at 16mhz, would I need to adjust the CAN timing to fix that?

[nopnop2002]

would I need to adjust the CAN timing to fix that?

Yes.

You can use this for CAN Bit Time Calculation.

http://www.bittiming.can-wiki.info/