Beta XRP only works when tethered via USB?

General
1

I’ve been experimenting with the Beta XRP hardware, and I’ve found that it only appears to work when the host computer is connected via USB to the controller board, rather than being able to support fully wireless connections to the unit (as the Romi was able to do). Even if I have the battery power turned on, the unit immediately disconnects from the host/simulator when I unplug the USB cable.

Is this expected behavior? If so, is it something that will be corrected in an updated build, or in non-Beta XRP hardware? (And if it’s not expected behavior, are there any suggestions as to what I need to do in order to remove this constraint?)

As context, I’m running the 0.4.0 Alpha firmware on the XRP, and using the Alpha 1 release of the WPILib software on the host. (I see that the latest firmware is 0.5.1, and I’ll try updating to that when I can later this weekend.)

2

Good question. When the XRP is being used in the FRC / WPILib mode it actually only works over the WiFi and we don’t send any data across the USB cable. But, the USB cable does provide power to the XRP control board if it is not being powered by the batteries.
Check that the power switch is on, that no batteries were accidently put in, in the wrong direction. That the barrel connector is secure.

XRP_Controller-Power
XRP_Controller-Power1500×1500 361 KB

You will know that the power is correct when both of the red LEDs come on, on the control board.
XRP_Controller-LEDs
XRP_Controller-LEDs1500×1500 340 KB

3

I don’t have it in front of me to check right now, but given that at least one of the motors was running, and I assume that that can’t happen via USB power alone, I think it was fully connected for battery power.

But I’ll try when I can, and follow up here with results.

4

Hi there!

I believe the problem is a version mismatch between WPILib and the XRP firmware. WPILib 2024 Alpha 1 is intended to be used with at least firmware v0.5.x, the networking got an overhaul in this update that is not backwards compatible.

Once you get the firmware updated on the XRP, I’d recommend starting out with this WPILib example: GitHub - bb-frc-workshops/xrp-2024-alpha-example (Note, I believe you’ll need to change the IP address in line 64 of build.gradle to 192.168.42.1)

Also use v0.5.1 of the XRP firmware, v0.5.0 had a bug in it with the ultrasonic sensor: Release XRP-WPILib Firmware v0.5.1 · wpilibsuite/xrp-wpilib-firmware · GitHub

Please let us know how it goes, we’d love to hear any feedback you have!

1 Like