No USB data connection on P1?


I’m having trouble getting a P1 on a custom PCB to talk to my computer via USB. I have the Particle driver installed and have had no issues with the Core or Photon. However, with serial enabled, the P1 does not show up as a device on my Windows computer.

Is there a way to troubleshoot this? I have D+ and D- connected to pins 61 and 62, with a 22ohm resistor in between each one and the USB pin. Both show positive 1.85V, but I’m not sure what to make of it.

Thanks for looking!

Hi @zz1

I remember I had the same problem when programming my first P1 after using photons, I too originally thought it was a hardware problem but I think reinstalling the zadig driver might have done the trick… Give that a try anyway, it was a while ago so I’m having trouble remembering!

@zz1, there are two drivers to install on windows - the serial device driver for the P1 and the DFU driver via zadig. The latest Windows driver files can be download here and make sure you have the latest zadig and install the libusbK driver. You may need to manually install the serial driver. On my system, the P1 was tagged as a teensy device (I also use teensy) so I have to override the driver. :smile:

Any drivers necessary for a Mac? Same issue with USB connection for P1 on a Mac, but I assumed it doesn’t need any drivers since the Photon doesn’t.

Thanks for the suggestions! I manually installed both P1 and Zadig’s libusbK drivers. Unfortunately, when I plug in the P1, Windows shows no reaction whatsover, no Teensy, P1, nor even a chime followed by an unknown USB device. Apart from the P1 getting power, it’s as if nothing was plugged in at all.

Hey zz1, any luck?

I’ve had issues getting reliable solder connections on my prototype P1 boards. A handful of times I had the same issue with USB and reflowing the board solved it. ( And I had similar problems with JTAG, I2C, UART1, GPIOs … )

For your reference, With no USB plugged in, D+ is pulled up to 3.3V and D- is floating around 0.8V.
With a USB plugged (and detected by my laptop) in I get D+ pulled up to 3.0V and D- is pulled down to about 0V. I’m powering my P1 with 3.3V.