USBD on a custom 52840 board

[nasinn]

Hi, 

I am working on a custom board with the 52840 chip. The problem I'm facing is that when I plug in my custom board, Windows 10 immediately shows a USB malfunction error. This happens even when only the blinky example is loaded on to the board.

I realize there could be a number of hardware issues that prevent it from working, i.e. improper pad connection or improper design of the data traces pair, but the design in terms of components should be the same as on the DK. So before I start messing with the hardware, is there any necessary procedure to get the USBD to function on a SoC fresh out of the box? I think it's strange that I get the error even when there is no usbd firmware loaded on to the chip, but like I say, most likely hardware.

Best regards, Jonas

[Turbo J]

> is there any necessary procedure to get the USBD to function on a SoC fresh out of the box

Yes. You have to flash one of the USB example projects - otherwise the USBD hardware will not work. 

Blinky example has no USB code.

[nasinn]

This I do realize. I've flashed the cdc acm examples and I still the error when I plug it in. When you flash the DK with blinky and plug it in, Windows doesn't recognize any USB device as far as I can see, so that's why I thought it was strange that when I plug in my custom board with blinky, expecting nothing to happen, it says malfunctioned.

This is why I think it's a hardware problem on my side, but before I start messing with that I wanted to make sure there's no special procedure required to get it to work on a new chip, which would've been done in the production of the DK or whatever.

[Turbo J]

Note that windows can only recognize an usb device if either D+ or D- is pulled high via resistor or port pin. You might want to check for soldering/wirering errors.

[nasinn]

After excluding something wrong in terms of firmware, many thanks. I took a look into the schematics, which I confirmed are the same as the USB interface design on the DK. I then took a look at the components on the board, and it turns out I soldered the diode 90 degrees off... So now it works like a charm.