ST-link ISOL lost settings

[Hae Ryon Jung]

Posted on May 28, 2018 at 12:46

Hi All, 

I have tried to connect my custom target board with ST-link/V2 ISOL.

when I run STM32 ST-Link Utility, it looks OK, setting is captured as follows

after connect 20 pin JTAG cable to my custom board, STM32F103RF with empty flash.(I haven't flash it yet)

few seconds later, setting is changed as follows,

after error, I have to disconnect and reconnect USB cable connected to PC, and re-run ST-link utility.

Would you please let me know what is wrong with my setting or connection ?

FYI, ST-link/V2 is updated with latest firmware.

Thanks in advance.

Best Regards,

Hae Ryong

[Pavel A.]

Posted on May 28, 2018 at 13:25

Even on the 1st picture the target could not be detected. Not a good sign. 

Try to lower the frequency?

-- pa

[Tesla DeLorean]

Posted on May 28, 2018 at 14:26

Is the interface powered via VTarget on pin 1 or 2?

[Hae Ryon Jung]

Posted on May 29, 2018 at 03:44

Connection is as follows

1, 2 : 3.3V power

7 : SWDIO

9 : SWCLK

15 : NRST

remains are GND or open

I have checked NRST pin, when I started connect, then it went to LOW and never went back to HIGH.

Any Idea about why NRST stays at LOW ?

[Hae Ryon Jung · Accepted solution]

Posted on May 29, 2018 at 06:02

Hi All, 

Thanks for your feedback.

I have found the cause of error, we have designed SWDIO, SWDCLK pin as GPIO for later use, so there are capacitors connected on the line, it may cause signal error.

When we removed capacitors, ST link worked OK.

[Tesla DeLorean]

Posted on May 29, 2018 at 04:08

Check VDDA supply, this powers the POR circuit which can clamp NRST low.

[Hae Ryon Jung]

Posted on May 29, 2018 at 04:20

Target -> Settings 

when I tried to change Frequency at Settings menu, it showed as follows and I could not try connection for error

[Hae Ryon Jung]

Posted on May 29, 2018 at 04:24

Thanks for your prompt feedback

I have checked VDDA pin of STM32F103 chipset.

before I tried connection, it was 3.3V, and when I tried to connect, it went to LOW and stayed 

following is trace.log, FYI

===============

cErrLog::SetLogTraceOn

STLinkUSBDriver.dll loadedST-Link/V2 device detectedTarget voltage detected: 3.461933Driving NRST lowError getting target IDCODE: if SWD, check SWD connectionError (4) while initializing ST-Link in SWD modeST-Link/V2 device detectedTarget voltage detected: 3.461933Driving NRST lowError getting target IDCODE: if SWD, check SWD connectionError (4) while initializing ST-Link in SWD modeST-Link/V2 device detectedTarget voltage detected: 3.450888Driving NRST lowError getting target IDCODE: if SWD, check SWD connectionError (4) while initializing ST-Link in SWD modeST-Link/V2 device detectedTarget voltage detected: 3.463511Driving NRST lowError getting target IDCODE: if SWD, check SWD connectionError (4) while initializing ST-Link in SWD mode

=============