4 years, 11 months ago.

CAN BUS don't work

Hi, anyone have reach the functionality of CAN module with 746NG? I have try some example and coding. I'm able to send the data over the bus correctly but i don't receive nothing. The signal fisically reach the processor chip and are into correct format (see with signal and protocol analizer). Help me, please, any information is good.

Question relating to:

The STM32F746G-DISCO discovery board (32F746GDISCOVERY) is a complete demonstration and development platform for STMicroelectronics ARM® Cortex®-M7 core-based STM32F746NGH6 microcontroller.

Ciao, ti rispondo in italiano. Io uso il can con questa scheda e funziona perfettamente. Comunico in can anche tra F746Ng e F303RE. Ho avuto inizialmente problemi per settare la velocita, poi superati forse con gli aggiornamenti software. Sicuramente lo saprai, ma senza terminatori sulla linea, oltre 30 - 50 cm il can non funziona piu'. Se hai bisogno di ulteriori informazioni, chiedi tranqquillamente

posted by Franco Maffei 21 Nov 2017

1 Answer

4 years, 11 months ago.

Have you read the documentation of the board? http://www.st.com/content/ccc/resource/technical/document/user_manual/f0/14/c1/b9/95/6d/40/4d/DM00190424.pdf/files/DM00190424.pdf/jcr:content/translations/en.DM00190424.pdf Check page 37! PB8 and PB9 (CAN1 RD, CAN1 TD) connected as I2C (I2C1 SCLI2C1 SCL, I2C1 SDA), and pulled up to Vcc with 2k7. I think you should remove those resistors.

http://www.st.com/content/ccc/resource/technical/document/datasheet/96/ed/61/9b/e0/6c/45/0b/DM00166116.pdf/files/DM00166116.pdf/jcr:content/translations/en.DM00166116.pdf Check page 71! LCD_B6 line is also on PB8, and LCD_B7 line is on PB9. Maybe you could not use CAN and LCD simultaneously, or maybe you have to cut the trace to the LCD. There is the same problem on STM32F429 Discovery board.

Accepted Answer

Hi Mark, thank's for answer. I have checked your suggestion and it's possible to have reason about pullup resistor but, about lcd connections, if you see the linked document (page 37) you can verify which PB8 and PB9 are't connected to lcd. So, i can try to leave I2C resistor and verify if it's the problem. Bye. http://www.st.com/content/ccc/resource/technical/document/user_manual/f0/14/c1/b9/95/6d/40/4d/DM00190424.pdf/files/DM00190424.pdf/jcr:content/translations/en.DM00190424.pdf

posted by Neri Tiziano 29 Oct 2017