CODEWITHSUNDEEP
embeddedstm32stm32f4st-link
larts
larts

Reputation: 67

ST-LINK could not connect to the target

I'm trying to connect to stm32f401rbt6 with st-link utility.

The MCU has 6 pins connected, as on the image below.

The target is powered by a lab power supply, target GND is connected to the ST-Link GND

When I plug it to the computer, st-link utility says it can't connect.

MCU connection

Tried:

The issue is still remain. Please suggest what I'm doing wrong, or how to check that my MCU is alive.

Upvotes: 1

Views: 6491

Answers (3)

Alexandre Dock
Alexandre Dock

Reputation: 1

i had same problem. It happens when flash an wrong code and STM32 can not boot by flash memory any more. You need boot by system, connect Boot0 to Vcc and connect through an usart adapter, Tx to PA10, Rx to PA9, Vcc and Gnd, Just this. Use STM32 cube programmer, option usart, click connect(It works!) and at erase&programming menu , click start programming a correct code. Now You can again use stlink!! with Boot0 to Gnd. That is it !!

Upvotes: 0

Assay
Assay

Reputation: 146

(Similar question: Stm32CubeProgrammer not connecting (no error msg) using ST-LINK V2 dongle and Lora E5 mini board)

You can try the following suggestions. Some ST devices are a lot more sensitive than others when it comes to programming. I have had some ST devices programming without issues and then using practically the same setup on other devices it just won't work.

  1. Place a 22ohm resistor in series on the SWDIO and SWCLK lines. This link suggests only placing it on the SWDIO line but I found that I needed it on the SWCLK line as well. Typical SWD Circuit

  2. For the ST Link Settings try using these:

    • Reduce the frequency from 4MHz to a lower frequency
    • Use SWD
    • Use connect under reset

  3. Don't use an external pull-up on the NRST line.

  4. Make sure that your programming wires between the ST-LINK and the target board are as short as is conveniently possible.

  5. (This one I must stress as being important) Make sure that your processor's ground pins are all connected very closely together (i.e. the tracks between them are as short as possible) and that very importantly your programmer ground is also connected to the same ground pins very closely.- At high programming speeds a thin or long unbalanced (different length) ground track to the processor can cause a problem with some devices.

  6. Whatever you are using to supply power to the processor must have a supply with a similar voltage as the ST-LINK (mine is 3V) - (although I have found that if the processor supply is 3.3V programming seems to still work most of the time.) (Remember the original ST-Link does not supply power only reads the power level.)

  7. A dodgy programming setup can accidentally set the protection to LEVEL 2 bricking your device - so if you have been trying and not getting any further, it might be time to replace your IC.

  8. Prior to changing / erasing a device that had been programmed to LEVEL 1, you might need to first enable the PCROP_RDP option byte. - Once enabled, you should be able to change from LEVEL 1 to LEVEL 0 that will automatically erase the device.

  9. Some people have suggested holding the device in reset until just after pressing the erase button to enable erasing it.

I hope these suggestions help...

Upvotes: 0

PhilM
PhilM

Reputation: 66

I once had similiar issues and i figuered out, that decoupling capacitors were vital. After soldering this onto the pcb, it worked like a charm.

Upvotes: 3

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