Tuesday, May 22nd 2018, 7:41pm UTC+2

You are not logged in.

  • Login
  • Register

Dear visitor, welcome to SEGGER Forum. If this is your first visit here, please read the Help. It explains how this page works. You must be registered before you can use all the page's features. Please use the registration form, to register here or read more information about the registration process. If you are already registered, please login here.



Date of registration: Nov 15th 2017

Posts: 1


Friday, January 19th 2018, 7:25am

[SOLVED] URGENT PLEASE HELP! "no cortex M SW device found"


A month ago, I had a fully working development suite...i.e. Keil V5, Jlink, STM32L031-device/eval board.

After coming back to the project after some weeks, for no apparent reason I now receive the error message "no cortex M SW device found" when I try to download to flash.THERE HAVE BEEN NO HARDWARE, SOFTWARE, TOOL-CONFIG CHANGES MADE. I have even kept screen-captures of all my settings and everything looks as it did before.

There is something inherently unstable about this Jlink device, the driver and/or Keil.

Can someone please assist - our company is running behind now due to this! ...I think this must be a known error given the amount of posts I've seen about this, however NONE of the solutions presented had any impact.

from the output:

Set JLink Project File to "C:\Users\py\Desktop\Work In Progress\Projects\Segment Remote\Embedded\MDK-ARM\JLinkSettings.ini"
* JLink Info: Device "STM32L031K6" selected.

JLink info:
DLL: V6.20h, compiled Oct 27 2017 16:22:47
Firmware: J-Link V10 compiled Oct 6 2017 16:37:55
Hardware: V10.10
S/N : 50105710
Feature(s) : GDB

* JLink Info: Found SW-DP with ID 0x0BC11477
* JLink Info: STM32 (connect): Can not attach to CPU. Trying connect under reset.
* JLink Info: Found SW-DP with ID 0x0BC11477
* JLink Info: Found SW-DP with ID 0x0BC11477
* JLink Info: STM32 (connect): Can not attach to CPU. Trying connect under reset.
* JLink Info: Found SW-DP with ID 0x0BC11477
***JLink Error: STM32: Connecting to CPU via connect under reset failed.
Error: Flash Download failed - Target DLL has been cancelled
Flash Load finished at 17:10:23


Super Moderator

Date of registration: Jan 2nd 2017

Posts: 1,048


Friday, January 19th 2018, 4:25pm


Thank you for your inquiry.
Such an issue is not known to us.
Could you try connecting to the target device using the J-Link Commander? https://wiki.segger.com/J-Link_cannot_co…-Link_Commander
Could you post a picture of your Commander output when you try to connect?

What is the J-Link log output when using GDB? https://wiki.segger.com/Enable_J-Link_log_file

Could you post the log file?

Best regards,
Please read the forum rules before posting: Forum Rules

Keep in mind, this is not a support forum. Its main purpose is user to user interaction.
Our engineers will try to answer your questions between their projects if possible but this can be delayed by longer periods of time.
Should you be entitled to support contact us per e-mail.
The following contact form can be used for this: https://www.segger.com/about-us/contact-us/


Super Moderator

Date of registration: Dec 18th 2007

Posts: 1,516


Friday, January 19th 2018, 5:34pm

As you did not change your tools, setup, SW versions etc.
there are only 2 things left:

1) You have have a bad cable etc. that has bad/unstable connection to your HW

2) You have changed your application to enter low power modes that inhibit debugger connections

reg. 2)
Do you have the nRESET pin of the ST device connected to J-Link, so J-Link can control it?
It is mandatory to make sure that J-Link can connect to your device, no matter in what state it is.

- Alex