Custom Board with G120E


I have created a custom board with G120E module.

I connected it with the usb debug on PC and this one can’t detect my board.

For using/debug the G120E on a custom board, which uUSB connector is needed (basing in G120E development board) ?

Thanks in advance.

Have a good day !

All you need is 3.3V and usb connector really. Of course make sure reset and mode pins are set properly.

Thanks for response.

Just one uUSB is necessary exactly ?
Mode pin need to set high or low ?
On of Development kit G120E , mode pin are no connect, normal ?

Thanks and sorry for my english.

@ Chris28495 - have you taken a look at the datasheet? It is a good resource.


I looked a datasheet : [b][/b] for G120E.

Chapter Device Startup.

I don’t really understand all. I think Mode pin need to set high for USB.
I set high mode pin and after I connect PC my board with USB Debug ( USBC D- and USBC D+ ). No reaction on PC.

Am I irrelevant?


Are you sure the usb pins are not reversed?

Mode PIN is set low for USB on G120E exactly because high is for COM1?

On schematic, yes, i not reverse the pin USB.

Check image.

Thanks a lot

How does the routing to the connector look? Has it been laid out using differential pair? Is the PCB foot print correct? You’d be surprised by this if you didn’t create it yourself.

Do you have ESD protection on the lines?

I leave the mode pin unconnected and USB works this way.

One thing I recently hit was the rise time on the power supply. Because the design was to meet CISPR25 standards, it was slow to rise and would lock up.

What do you have on the reset input? I increased the resistor value to hold it in reset longer. You can check if this it the problem by powering up and pressing reset. If the device now connects on USB, your rise time is too slow so you need to hold reset longer.

Set this LOW. G120 is HIGH but G120E is low :frowning:

I set a MODE pin on low state directly with a wire just for debug and check.

No effect.

Later, i set a mode pin on low state with pull-down and this resolve my problem…

First using of module G120E in my school for a work of graduate.

Thanks for your help.