STM32WB55REV6: Failed to get programmed via SWD

[turjman]

Hello everyone,

I'm a fairly experienced STM32 Developer, and I use the STM32 line almost in all of my designs.
However, I've encountered an extraordinary problem.

I've followed this Application note: AN5290 in my schematic (see attachment).

However, I cannot program it via SWD.

I've supplied +5V and checked that all +3V3 rails are present and OK.

When I try to program it via STLINK-V3 (official, not the clone) it cannot access the MCU and says "No STM32 Target Found".

I've connected the MCU USB to my computer and showed that the MCU is in DFU Mode even though BOOT0 is pulled LOW.

Another strange thing is that Option bits are assigned strangely.

I've uploaded the code in the attachments via USB DFU mode and the Code has worked perfectly.
However, I cannot program it again even via SWD or DFU which is very strange behavior.

The board consumes around 10mA in DFU or Runs the code in the attachments.

Thanks.

[AScha.3]

Hi,

> When I try to program it via STLINK-V3 (official, not the clone) it cannot access the MCU and says "No STM32 Target Found".

btw there is no V3 "clone" , afaik.

Try cubeProgrammer with: st-link mode,  hardware reset, connect under reset. (and nrst connected to st-link...)

-> show, what its telling.

[turjman · Accepted solution]

Hi, @AScha.3 

I've figured out where is the problem.
I didn't connect the VCC pin in the STLINK-V3 to my Target +3V3 Rail.
So the Target Voltage always shows Zero.

When I connected the VCC pin to my Target +3V3 Rail now everything came back to normal.

Thanks.