How to use the standalone ST-LINK capability of my nucleo after I cut the PCB?

[BCora.1]

Hello,

in the user manual of my Nucleo L152RE, on page 16, it's written:

"""

Cuttable PCB

The STM32 Nucleo board is divided into two parts: ST-LINK part and target STM32 part.

The ST-LINK part of the PCB can be cut out to reduce the board size. In this case the

remaining target STM32 part can only be powered by VIN, E5V and 3.3V on ST morpho

connector CN7 or VIN and 3.3V on Arduino connector CN6. It is still possible to use the

ST-LINK part to program the main STM32 using wires between CN4 and SWD signals

available on ST morpho connector (SWCLK CN7 pin 15 and SWDIO CN7 pin 13).

"""

(source: https://www.st.com/resource/en/user_manual/dm00105823-stm32-nucleo64-boards-mb1136-stmicroelectronics.pdf#page=16 )

So I'd be very happy to cut my board into two parts. I could power the MCU part with a 3V battery when I only need to run my program. And I could connect the MCU back to the ST-LINK part using jumper cables when I need to flash the microcontroller again. That would be awesome.

But I'm not sure I understand what pin I should connect to what pin to reconnect the ST-LINK to the MCU. I must connect the pin 15 of CN7 to what and the pin 17 of CN7 to what?

I can see the CN4/SWD block on the ST-LINK part of the board but there are 5 pins here, not two. So what do I have to connect to exactly?

[TDK]

Yes, but now we're talking in circles.

Read "6.3 Power supply and power selection" in the user manual to see the various options for power. There are multiple options to provide flexibility.

The power supply is provided either by the host PC through the USB cable, or by an external source: VIN (7V-12V), E5V (5V) or +3.3V power supply pins on CN6 or CN7.