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stm32f070 wont connect to st link

Jesus Perez
Associate

‎2017-08-11 06:05 PM

Posted on August 12, 2017 at 03:05

I am connecting a standalone board with a STM32f070 to a ST Link v2, but regardless all my efforts ST Link is unable to detect the MCU and I can not program it, I can not found any information about this issue, it seems everyone has done it straight forward with no issues. I am attaching some pics in how I am trying to connect the device to ST Link, I followed the schematics from ST official site with no results.

I have connected VCC 3.3 to board, I am sure GND is ok and jumper for programming is set.

Preview file
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Preview file
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3 REPLIES 3
juozas
Associate III

‎2018-02-15 02:35 AM

Posted on February 15, 2018 at 11:35

I have found influence of some capacitance on SWCLK pin on my board connector - by probing with oscilloscope. After soldering 12pF to my board between SWCLK and GND, my STLINK and debug with EMBITZ have start to work perfectly.

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Szymon PANECKI
Senior III

‎2018-02-15 04:10 AM

Posted on February 15, 2018 at 13:10

Hello Jesus Perez,

I made a review of your schematics. Let me share with you its outcome:

Supply pins

  • VDD pins and VDDA pin are connected ok.
  • VSS pins and VSSA pin are connected ok.

Reset pin

  • Perfectly fine: 100nF between NRST and ground is a minimum needed circuitry.

BOOT pin

  • I would suggest to remove R1. Instead I would suggest to insert 10k resistor betwenn J3 and 3.3V.

Capacitors

  • Decoupling capacitors are completely missing. Each VDD/VDDA pins needs 100nF connected to ground.
  • Additionally please add 1uF capacitor between VDDA and ground.
  • Also one 4.7..10uF capacitor common for all VDD pins is recommended.

For more information please refer to

http://www.st.com/resource/en/application_note/dm00089834.pdf

. Below I attach a picture with reference schematics.0690X00000609ibQAA.png

Regards

Szymon
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gbm
Lead III

‎2018-02-15 11:16 PM

Posted on February 16, 2018 at 08:16

To keep the thing simple:

1. Short BOOT0 to GND.

2. Get rid of RESET capacitor.

3. Make sure to put the right supply decoupling capacitors close to VDD/GND pins.

4. Reduce SWCLK frequency to no more than 1 MHz - the most important thing to do.

5. You don't really need the RESET connection to ST-Link. Just make sure you don't change the default functions of SWCLK and SWDIO pins in your firmware.

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