Arm Mbed OS support forum

Mbed Studio does not flash Blinky to LPC1768

Today, I installed Mbed Studio (on Windows 10) and connected an Mbed LPC1768 target. I downloaded the mbed-os-example-blinky, build and compiled, using the debug icon. I folowed the instructions from the ARM Mbed Studio manual. Mbed Studio however does not flash the target, and I get two notifications:

  • Timeout waiting for gdb server to start;
  • Build of mbed-os-example-blinky completed: Program compliled;

‘dragging and dropping’ the binary from the Build directory however works.

Can anyone help me out?


please see this topic - Cannot debug with NXP LPC1768 - Mbed OS - Arm Mbed OS support forum.
Also the LPC1768 is missing on the list of boards what are officially enabled for debug.

BR, Jan

Jan, Thanks for your swift reply. That is a pitty.
Is that also the reason MBed Studio doesn’t flash the LPC1768?

I do not have this target so I can not test it but the Build and Deploy must work. If not then try to update mbed Interface Firmware.
Also for deploy without debug just use the Play button.

BR, Jan

Jan, thanks. I tried several combinations of build profile (‘Develop’ or ‘Release’), and Build (‘Hammer’) and Build & Run (‘Play’), but none of them flashes the target… Just continue my investigations :slightly_frowning_face:


I tested LPC1768 build by Mbed Studio 1.4.1 for both Win10 and MacOS.

[MacOS 11.3.1]

  • “Connect a platform and run” (Play) button makes erase and flash binary
  • … wait for the completion and press reset button manually makes program to run
  • LED1 blinks fine (program working ok)


  • “Connect a platform and run” (Play) button tries to erase, but the small status windows disappears quickly
  • Both “Build program” and “Connect a platform and run” button grayed out
  • I could not see the blinky program in my storage drive of the LPC1768
  • …nothing happen :frowning:



Same here :slightly_frowning_face:
And currently taking all processor resources, without any reason…

All, just got a message from the MBed Studio team, stating:
‘LPC1768 is not yet fully supported in Mbed Studio. Studio uses python tool called pyOCD for binary flashing and debugging a program on the board. Unfortunately, pyOCD fails to work correctly with that target. We are working with pyOCD maintainers to resolve this issue’

1 Like

After struggling for a while with similar issue(s), I came to the conclusion, that the best is to forget the Mbed Studio (tested both Win and Mac) and use Eclipse for the development. Not so fancy, but it works.

Besides that, forget the pyOCD and invest into a real HW JTAG debugger, if you want to do some serious development. I recommend Segger J-Link. Although it is not cheap, the time you will invest in making the things work outweighs the costs of it.

The low cost alternative to start with less pain is, to switch to a Mbed compatible board with an integrated JTAG debugger. E.g. STM-Fxx-DISCO boards , with detachable ST-Link.
In latter case avoid low-power CPU boards as this also does not work entirely well with Mbed Studio (e.g. STM-Lxx series, can be flashed but not debugged).