G120E hardware and USB

We have created board using the G120E SOC and wondering if we have connected the pins correctly, i assume according to our PCB design, that we should be able to plug it into my dev computer and the G120 will be picked up as a COM port so i can test the rest of the board.

See attachment for our setup. Is the bootloader loaded on shipment.

The schematic looks OK and the same as I am using.

Can you show the PCB routing on the connector? As you are using Altium, zoom in so you can read the net name and post a picture of the USB footprint as it is connected up. Just the USB part will be more than enough.

I assume you did use differential layout for the USB tracking? I don’t see any differential markings on the schematic. How long are they?

What is differential layout?

What I want to see is something like the attached. Zoom in on the PCB editor and then ALT+PRINT SCREEN to capture it.

Differential layout is used when you want the tracks to be similar length, space and width to meet certain criteria. If the lengths are very different then you can get delays on the signals. You don’t need the HIGH SPEED design for USB but you do need to try and keep tracks roughly the same length and if you do have to use VIA’s then make sure both tracks use the same number of them.

Can you confirm on the PCB footprint for the G120E that your USB is connected to pins 41 and 42 and the first pin on that side is pin 36?

My observation counts this as 40 and 41 if I assume the first pin is 36.

A zoomed in image of the pins in that area would help.

I’ve just spotted what might be your error. You have UD-D+ connected to pin 41 and pin 28 on the schematic. Pin 28 is VBAT and might explain why the USB fails to work.

@ Dave McLaughlin - i owe you a favor.

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Cool. Glad I could help.

Were you able to cut the track and get it working?

@ anthonys - Lolz. Someday he’ll call on you!