Error Message ''Unknown Target Connected''

[luis239955]

Posted on October 17, 2012 at 10:14

Hi Guys,

I have been playing with my STM32F4Discovery board for a few weeks now using the provided programs, but now I wrote one of my own and can not get it to work. I am using some of the files form the IO_Toogle example, the program is compiling and Linking fine with no errors at the end. I have selected the STM32F407VG as the target. When I try to load or even erase I get this error message: ''Unknown Target Connected''. same if I try to initiate a debug session. When I try to run the original IO_Toggle program, it loads and runs perfectly. I am at a loss here... Any Help will be much appreciated, as I am pulling my hair out. Best Regards                     Luis

[Tesla DeLorean]

Posted on October 17, 2012 at 16:25

On what tool chain?

Have you set up the debug/flash to use JTAG pod in SWD mode? Have you tried cloning one of the project examples/templates, building a project from scratch assumes you get a lot of hidden settings/configurations correct.

[emil2399]

Posted on March 07, 2013 at 15:12

Please check the following settings regarding to the microcontroller you use.

[Tesla DeLorean]

Posted on March 07, 2013 at 16:40

That's more likely to get you an ''Error : Flash download failed'' condition.

No Algorithm found for: 08000000H - 0800256FH Erase skipped! The error mentioned often occurs as a result of the part not being powered, JTAG used instead of SWD, or the part being generally unresponsive to the debugger.

[frankmeyer9]

Posted on March 07, 2013 at 16:52

Depending on the MDK version, I would try both ''ST-Link'' and ST-Link(Deprecated)'' as debug adapter.

And, as clive suggested, check that it is actually set to SWD (for the discovery-integrated version).

[Linda]

Posted on May 22, 2014 at 16:34

After I foolishly  connected 3v to PF9, then It happened ''Unknown Target Connected''. I am not sure it is coincident, or that connection caused some problem in hardware  .

Please help

[Tesla DeLorean]

Posted on May 22, 2014 at 16:53

Please help

I'm not sure what that would be. If you evaporated the silicon you would need to replace the part(s) that were destroyed. Check the supplies, and VCAP pins (on F2/F4 parts) In terms of signs of life from the STM32, you could reboot with BOOT0 = High, and either use USART1 (or others per device) and test the System Loader's response to 0x7F sent at 9600 8E1, or USB DFU mode.

[frankmeyer9]

Posted on May 22, 2014 at 16:58

If the target was powered at that time, this should not cause problems.

But if it was not, and the 3V was only applied to the GPIO pin, your target MCU might be dead, or damaged beyond repair.

[Linda]

Posted on May 22, 2014 at 17:18

It was powered.

which one I should choose, JTAG or SW? I am using Keil 4. Thanks

[Tesla DeLorean]

Posted on May 22, 2014 at 17:28

It was powered. Can I use 100k resistor to connect to 3v to reboot it?

Can you? As you have the broken board, only you are going to be able to diagnose the problem. You might have to identify and replace the part(s) which were damaged. Start by looking at the supplies.