I am using STLink V3 set to program the F103RB Nucleo board using SWDIO interface. The board works fine when connected to PC using the on-board STlink debugger but when I use external STlink device to program it, it says "Can not connect to target!". I have removed on-board STlink debugger jumpers so that I can use external one. My connection from Stlink V3 to F103RB Nucleo (CN4 Header)
are as follows:
Clock->Clock, GND->GND, SWDIO->SWDIO, NRST->NRST,VCC->NOT CONNECTED (Even if I connect, it doesn't work)
The datasheet says that "SB12 NRST (target MCU RESET) must be OFF if CN4 pin 5 is used in the external application", is this the problem ? How to resolve that ? or is there any other potential reason for this error.
I'll really appreciate prompt responses. Thanks
CN4 connector is connected to on-board ST-LINK, which is used when you use on-board ST-LINK to program/debug an external device.
You need to access pins of the main uC using other connectors.
Please see this answer: https://electronics.stackexchange.com/questions/566511/how-can-i-program-a-stm32-nucleo-board-without-using-the-on-board-st-link/566515#566515