STM32WB05KN co-processor USART is not responding (bluetooth)

[Harry_bee]

Hello, hope someone can help me, thx!

I successfully completed the SensorDemo_BLESensor-App by connecting NUCLEOWB05KN1 with NUCLEO-U575ZI-Q, and carefully followed the manual X-CUBE-WB05N_GettingStarted. I have also verified that we can send data by Bluetooth on NUCLEOWB05KN by only connecting the VDD, GND, and the RX, TX to the TX and RX of the NUCLEO-U575ZI-Q. 

However, we built a PCB that exactly copy from stdes-wb05kv2ld (two-layer board), and assembled the stm32wb05kn and the components (same as stdes-wb05kv2ld) onto the PCB. When we connected the PCB with NUCLEO-U575ZI-Q by 3V3, GND, RX to PCB's USART TX, and TX to PCB's USART RX, the WB05KN is not responding; by the logic analyzer, we can see that the NUCLEO-U575ZI' TX is sending out the data, but stm32wb05kn is not responding; it remains logic high.

I was thinking if the chip has been lock-up accidentally, so we have also tried the stm32programmer, by connecting the swdio, swclk, NRST, 3V3 and GND to st-link, the stm32programmer said that no device connected, but thestm32programmer can recognize the NUCLEOWB05KN1.

Meanwhile, using an oscilloscope, we can see the SMPS. There is a high-frequency voltage feeding the VFBSD pin. The multimeter verified that all the connections were connected.

So, for the STM32WB05KN co-processor, we can just use the NUCLEO-U575ZI-Q default example (SensorDemo_BLESensor-App) setting to communicate with it by USART without any other settings(like updating the firmware, an extra event to wake-up the chip rather than the start pulse...), right?

And is there anything we should check? Or do you think the chip accidentally died?

[STTwo-32 · Accepted solution]

Hello @Harry_bee 

This is normal since the X-NUCLEO-WB05KN1 contain a firmware that configure the shield to communicate with a Host. Without a similar FW, you design is a board and not a module controlled by a Host. The firmware of the X-NUCLEO-WB05KN1 is available under Utilities\DTM_Controller_Only on the X-Cube-WB05N. 

Best Regards.

STTwo-32

[Harry_bee]

Hi STTwo-32,

Thanks for your insightful information. I will try to assemble a new board with this chip to rule out the bad chip assumption first, and I will try to upload the DTM_UART_WITH_UPDATER_CONTROLLER.hex in the Utilities\DTM_Controller_Only path by STM32CubeProgrammer.

• And for another issue I demonstrated here before:
  
  ---''by connecting the swdio, swclk, NRST, 3V3 and GND to st-link, the stm32programmer said that no device connected, but the stm32programmer can recognize the NUCLEOWB05KN1 with same connection"
  
  Do you have any further suggestions? Do I need to do anything else to "wake up" the new chip without firmware yet, or do you think this could be only about the connection or bad chip issue?  I have connected the NRST to 3V3 with 10k and to GND as well with a 0.1uf capacitor.

Thanks again for your help and support!

Best,