I recently received a couple of PGA2350s and I’ve been having a lot of fun messing with the RP2350. However, when I initially wired up the board after soldering on all the headers, my computer refused to recognize it properly. I checked Device Manager and found that it appeared as “Unknown USB Device (Device Descriptor Request Failed)”.
After a few hours of troubleshooting, I discovered the issue. Rather than use a breakout board, I instead used a USB cable with female jumpers on the end. I wired the USB lines according to the label colors on the PGA2350 pinout diagram on the product page:
- VBUS to red
- GND to black
- USB DP to white
- USB DM to green
However, I later realized that the diagram is incorrect, and that the colors should be:
- VBUS to red
- GND to black
- USB DP to green
- USB DM to white
There is a second photo on the product page showing the PGA2350 connected to a mini breadboard with a USB breakout and a couple of switches. I mention it because the wire colors in this photo are also incorrect.
So, to clarify, my board is working, and I’m quite happy with it, but I figured I’d let you guys know about this to hopefully save others time in the future.
It worked OK for me wired up as shown in the diagram on the product page. I think you will find that the green and white wires in your cable are wired the other way around. I don’t think there is any standard as far as what color the wires are in a USB cable?
I used this, USB DIY Connector Shell - Type A Male Plug : ID 1387 : Adafruit Industries, Unique & fun DIY electronics and kits
I could have used any colors I wanted but I did match them up as per the diagram.
On a side not, what uf2 did you flash yours with?
Here’s the cable I’m using: USB Type A Plug Breakout Cable with Premium Female Jumpers - 30cm long.
I am aware that there’s no standard for USB wire colors, but the cable I’m using and every other USB cable I’ve cut open have used green for DP and white for DM - this is also how it’s listed on Wikipedia. I realize that it’s somewhat of a regional thing (I’m in the US, if that matters) but most other USB wire color schemes use totally different colors, so I’m operating under the assumption that the diagram is trying to adhere to the convention I’m used to.
As for your second question, I’m programming in C++ and flashing the compiled ELF using picotool, so I guess the answer would be that I’m not using a UF2 at all.
For that cable, as per its product page.
- Green connects to D+ data positive
- White connects to D- data negative
That is the other way around if you go by the colors used by Pimoroni. Which I believe are just arbitrary. They could have used blue and orange if they wanted.
Anyway, at least you figured it out. It is a pain when your head scratching, been there done that, numerous times.
OK, I went with the Pimoroni Micro Python no psram uf2. Other than flashing it with Micro Python I have yet to do any tinkering with mine.
Thanks for raising this. I swear I checked that the colours were correct for what a USB cable should be, but as is typical I can no longer find my source!
I also used these colours on the Pico Vision Pins & Dims, which may have given also me false confidence they were correct.
If someone has a definitive source (more than the questionable google image results) please link me to it. I’ll then get the diagrams updated. Getting the photo updated may take longer, as that involves another member of our team, and I’m not sure I still have that breadboard set up any more.
I honestly didn’t think there were set colors for a USB cable, and it looks like I was wrong. Apologies to @nununoisy for that.
I couldn’t find anything official, but it does look like its.
- Green connects to D+ data positive
- White connects to D- data negative
Looks like I’ll be getting my soldering iron out and swapping them around.
