title: STM32F407 Disc E31 Error message in debugging
body: <p>I will ask a question about my STM32F407 Discovery board. I want to learn about external interrupts and I was making a small circuit. I connected PH0 to my button and PH1 to the LED. But these pins are connected to the mcu's crystal pins. But I didn't know it at that time. I was press button that is connectet to 5V. And my IDE won't connect to my board for debugging debugging. I can connecting to my board via ST Link Utility and I can do a full chip erase with no errors. Then I turn back to code in Atollic, press the debugging button and I get this error messages:</p>
  <pre><code>Error in executing 'cont' command ... 
  CM4 Failed to read all registers
  FAILED to REGISTER Values from the target
  Target is not responding, retrying...
  
  *some messages in between*
  
  warning: Remote failure reply: E31
  Remote failure reply: E31
  Remote connection closed
  Quit
  </code></pre>
  <p>And then I turned off the debug screen to try again but I can't because Atollic can't find any ST Link devices. This is the error message:</p>
  <pre><code>Target no device found
  Error in initializing ST-LINK device.
  Reason: No device found on target.
  </code></pre>
  <p><strong>Note: My PC recognize my board in Device Manager.</strong></p>
  <p>How can I solve this problem. ST Link Utility connects to my board succesfully, My PC connects to my board. I tried St link firmware upgrade but I got more errors. Like this.</p>
  <p><code>Failure at line: 13 in &quot;Target Software Startup Scripts&quot;</code></p>