STM32Wl55CC connection error for SWD programming

[georgerambak]

I am trying to make a prototype from a perf-board and a QFN48 adapter using STM32WL55CC MCU based on the wiring in the pics below.  I want to connect to the MCU using SWD via an STlink attached to a Nucleo board. I already removed the 2 jumpers on CN2 and made the following connection shown below to CN4 and the MCU. However when i try to connect using the ST-Link utility I am getting the following error. BTW I just started learning embed development and just want to connect via SWD for now. 

Connection Details:

VDD_TARGET(PIN1 on CN4)=>3.3V supply from PIN16 CN7 on the nucleo board

SWCLK(PIN2 on CN4)=>PIN 42 on STM32Wl55CC

GND(PIN3 on CN4)=>ground pad on STM32Wl55CC

SWDIO(PIN4 on CN4)=>PIN 36 on STM32Wl55CC

NRST(PIN5 on CN4)=>NRST on TM32Wl55CC

VDD for the MCU is supply from 3.3V CN7 PIN16 of the nucleo board

[TDK]

What about all the other power connections? RF and SMPS? These do not seem optional even in LDO mode.

https://www.st.com/resource/en/datasheet/stm32wl55cc.pdf

Consider buying a known good board for development. Having decoupling caps so far from the chip is not ideal.

https://www.st.com/en/evaluation-tools/nucleo-wl55jc.html

[georgerambak]

Thanks for the feedback. Based on the reference design documentation (see pic) I came to the conclusion that the RF and SMPS are not needed for just connecting via SWD for programming. Also the I am using the MB1789_LP-LowBand_LowPower reference design as a guide. I did not use a Nucleo-Wl55 development board because I eventually will need to develop my own board if I am to deploy anything serious and I want to delve deeper into the hardware development side. 

 

[TDK]

I don't think the firmware programming diagram is meant to list all of the connections needed. Rather just those relevant to programming.

The schematic you included powers RF and SMPS nets as the datasheet specifies.