G120HDR 2.0, no connection


I’ve got a G120HDR 2.0 board which I would like to debug via a USB or serial connection.
My setup is shown in the picture. I’ve installed a switch betwenn P2.1 and GND to choose between serial communication on the “user slot” or USB communication on the “USB slot”.
The connection behaves quite similar in the two connection modes.

I use Windows 7 64 bit.


If i connect the device to the pc it is sometimes recognized as “GHI NETMF Debug Interface” in the device manager.
Independend from that the board is sometimes recognized as “G120_G120HDR” in the FEZConfig.
If I try to ping the device in FEZConfig (when its recognized) after some seconds I get “Failure - Device is not connected or not responding.” and the status always goes over to “Status: No Device”.
Subsequently the board reconnects randomly.


The behavior is quite similar to the USB connection. The board is recognized sometimes as COM6 in the device manager.
If I try to ping the device I get the same failure and the status goes over to “Status: no Device”. After that the board reconnects randomly as described above.

If I go into “GHI Boot loader” mode (pressing down LDR0 and LDR1 and the reset) the behavior is also the same.

The interesting thing is that the day before, everything still works. I had only deployed some test code on the device. I’m not sure if that has anything to do with my problem.

If more Information is needed, I’d like to help.


Hi Bennift,welcome to the forum !

I can be pretty sure that this is caused by your test code. :slight_smile:

What happens is that the code runs, and doesn’t give any free time to the debugging engine on the chip, so when you try to do anything to it you get this type of lack of response.

Manually boot into tinybooter mode and reapply the firmware, and you should reliably see the device as expected.

In your apps from now on, it’s often not a bad practice to put a “delayed start” by either having something like a 3-second sleep using thread.sleep(3000), or even waiting for a button press before moving on with the main application code. That way the debugger gets plenty of time to connect and you can erase the app easier if you need.

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thank you! It worked!