Bootloader over SPI using a STM32U5A5 and STLINK-V3SET

[hiimron]

Hello all,

We are trying to get into the bootloader of the NUCLEO-U5A5ZJ-Q over SPI using a STLINK-V3SET. But are having issues with connecting the V3SET in the STM32Programmer and through the CLI, which is getting this error.

So far, we are seeing this happen on the SPI lines through a logic analyzer:

And we are not sure why...

We followed these two ST posts but neither post seem to be faring any success for our board combination:

- Solved: STM32H563 bootloader command over SPI - STMicroelectronics Community

- How to use STM32CubeProgrammer and the STLINK-V3SE... - STMicroelectronics Community

We have correctly applied the correct pattern from the AN2606 document, which is Pattern 12 for the STM32U595 and have this pinout between the boards:

SignalNucleo U5A5ST-Link V3

GND	CN7	CN6 pin 3
T_VCC	CN8 - 15 (VIN)	CN6 pin 1
SPI1_MOSI	CN7 pin 12 (SPI1 MISO)	CN9 pin 2
SPI1_MISO	CN7 pin 14 (SPI1 MOSI)	CN9 pin 3
SPI1_SCK	CN7 pin 10 (SPI1 SCK)	CN9 pin 4
SPI1_NSS	CN7 pin 16 (SPI1 CS)	CN9 pin

Are we missing something crucial or is this even possible for this particular Nucleo board?

[MHoll.2]

T_VCC must be the voltage used by the MCU, so You should not connect VIN (5V) but VDD (3.3V or 1.8V).

But in You case T_VCC is not used (The SPI interface is specified only for 3.0V to 3.6V signals).

The MCU is not responding to the STLINK.

- Have You tried to used the VCP interface provided by the integrated STLINK on the NUCLEO board, to verify that the MCU is in Boot mode?

- Have You tried to invert SPI1_MISO with SPI1_MOSI?

[hiimron]

Good point, the VCC of the V3SET expects 3.3V so we moved the pin to a 3.3V pin. 

We were able to successfully connect the Nucleo board to the bootloader using the VCP interface and getting this output from the log:

We did also switch the SPI pins a couple of times and does not seem to change behaviors. 

[hiimron]

Anyone have any updates to this or any other suggestions?