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SWDIO No target connected

Francesco Sfragara

I'm using a stm32f407vg board. Suddenly I can't download my code to flash memory. It gives me this error " Debugger - Cortex-M error: no target connected". In options for target > Debug > Settings in SW Device tab I see " SWDIO: Error No target connected".

How can I solve this?

Parents Reply Children
  • 0 in reply to Andy Neil

    I assume you are connecting using the on board debugger. If so, here are some ideas for troubleshooting a ST-Link.

    I) Test with a pack example

    • the pack example are already setup to work on a board. Verify with one of those examples. This rules out issues with your code.
    • In the Keil IDE, under Project-> Options for Target -> on the "Debug" tab, on the top right of the dialog, next the "USE: ST-Link Debugger, click the "Settings" button - the "Cortex-M Target Driver Setup" dialog appears.

    If the top right of the dialog says "No ST-Link detected", or on the top left, next to "Unit" the pull down box is empty: - Make sure there are no Windows USB drivers or board debugger firmware issues. If not - Swap out USB cables - Don't connect the ST-Link to your computer via USB hub

    If the box on the top left says - "Unknown target connected" - On the middle-left of the screen, in the 'Target Com" box, switch the Port from "JTAG" to "SW" - ST-LINK requires a Serial Wire interface, not JTAG.

    ======

    If that works, close the dialogues. Still using the sample pack example, Select Debug-> Start/ Stop debug session. If you get a pop up box, that says

    • "st-link usb communication error" then see "uVISION DEBUGGER: ST-LINK USB communication error" at www.keil.com/.../3662.htm
    • Internal command error, make sure to check the command window for additional information, then see: "uVISION DEBUGGER: ST-Link Does Not Connect to STM32F4 Discovery Board" at www.keil.com/.../3634.htm
      • Internal command error" and then "Error while attempting to read 64 bytes from memory 0x00000000"
      • Check the Boot jumpers on the board to make sure you are booting to the correct memory
      • Internal command error" A previous program running on the board is locking up.
        • Pull the BOOT0 or BOOT pin high, and restart the board, and perform a flash erase.
        • In the Keil IDE, under Project-> Options for Target -> on the "Debug" tab, on the top right of the dialog, next the "USE: ST-Link Debugger, click the "Settings" button - the "Cortex-M Target Driver Setup" dialog appears. Try using "connect under reset", close the dialogs and then perform a flash erase.
      • Try other connection/reset option "Connect under Reset"
    • Internal DLL Error, then see "Internal DLL Error Debugging with ST-Link" at www.keil.com/.../3666.htm
    • Finally, try the ST-LINK Utilities to erase and reconfigure the device