Why do we have 2 connectors namely CN2 (SWD) and CN3 (ST-LINK) on STM32F407 Discovery board? Are not they the same thing?
Electrical – SWD vs ST-LINK on STM32F4 Discovery board
debuggingstm32stm32f4stm32f4-discoveryswd
Related Solutions
The resulting error message indicates, that your PC is unable to find the ST Link altogether, can you try to disconnect your board from the CN2 connector and try again?
You should get something like "No MCU found" then, if you still get "Cannot connect to ST-Link" it would seem like your ST-Link is damaged or your USB cable is broken (that happens sometimes).
Your connections seem fine - check if you have no solder bridges on your board, if there is a short somewhere maybe that prevents the ST-Link from working correctly.
You'll need to isolate the microcontroller from the st-link portion of the board. To do this just remove the jumpers on the CN3 pins.
Then, to use your external st-link, make the following connections to the microconroller pin headers:
- SWDIO -> PA13
- SWCLK -> PA14
- GND -> GND
VAPP -> 3V/VDD
Do not connect the USB cable
Program it in SW mode.
Not sure why you'd want to do this, unless you wanted to use JTAG to program it instead. If that's the case let me know and I'll update the answer.
Best Answer
No, they're not the same.
The pair of jumpers on CN3 connects the ST-Link to the target device (i.e, the STM32F407 located on the Discovery board).
When those jumpers are removed, the SWD pins on CN1 can be used to connect the ST-Link to another target device.