STLink V3 CANBUS bootloader over STM32CubeProgrammer problem

[Linas L]

Hello,
In one of my boards I was planing to use CANBUS bootloader and STLink V3 with external canbus PHY to program MCU.

I was unable to program it, I can see STlink V3 does try to do some TX on CANBUS pin, but where is no packet available that could be decoded, just train of same duty cycle pulses.

Does any one had luck with STLink V3 and external CANBUS programming ? What I am doing wrong ?

• Yes, I added external TCAN1462VDRBRQ1 IC for programmer, and connected to RXD and TXD pins on STLINKV3_MDOS (RX 9, TX 10pin)
• Yes, I enabled externally TCAN1462VDRBRQ1 to be in active mode all the time
• Yes, I placed BOOT0 pin to high level when connecting power (same pin for power and BOOT)
• YES, STM32U585 uses PB8+PB9 as per datasheet for canbus bootloader

[Javier1]

What did you end up doing? coding your own FDCan bootloader host? or downgrading to classic can?

[Linas L]

I tested FDCAN bootloader, and it works with my own FDCAN controller, but not programmer. This is not that hard to implement, just like UART or any other bootloader.

Question do you have tools for it.

[Javier1]

Alright so you ended up creating your own FDCAN bootloader

[Linas L]

Well, not exactly, I was using internal bootloader with another STM32H7 that is controlled over USB to flash firmware over canbus.

So flash handling is done via STbootloader on U5 device, but commands are send via STM32H7 with windows controlling it

[Andrew Neil]

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@Linas L wrote:

I tested FDCAN bootloader, and it works with my own FDCAN controller, but not programmer.

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This seems to be a known limitation of CubeProgrammer (or, rather, ST-Link V3):

https://community.st.com/t5/stm32cubeprogrammer-mcus/accessing-fdcan-system-bootloader-with-stlink-v3-cubeprogrammer/m-p/764176/highlight/true#M7728