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Getting P2 Eval board connected — Parallax Forums

Getting P2 Eval board connected

Having some trouble getting my P2 Eval board going. If I connect the USB cable to PC USB port I get nothing, no lights. If I connect the same cable to AUX USB port I get an On light by that port and some on temporarily in the P56-P63 range. Does that seem like correct behavior?

Comments

  • VonSzarvasVonSzarvas Posts: 2,966
    edited 2023-01-21 07:46

    Could be a bad USB cable (one of the data lines not connecting), an issue at the PC USB port, massive overcurrent situation, or a blown P2 Eval board.

    Unplug any accessories (or stuff connected to your board).
    Check the shunt jumpers are in default positions. (3.3V and 1.8V jumpers on, 5V ACC jumper off).

    Then..

    I'd try a new USB cable first, followed by an alternative USB port, or even better, an externally powered hub so that all your experiments do not rely on the PCs power management.

    The behaviour at the AUX port seems correct, which would imply the issue is around the PC USB power-in area, or power-protection/power-switching circuit.

  • VonSzarvasVonSzarvas Posts: 2,966
    edited 2023-01-21 08:00

    One simple test....

    Power up the P2-EVAL board by the AUX connector, and then measure the voltage at each of the accessory header Vxxxx pins. For ease, your black probe can go to any of the four gnd posts or mounting holes as they are all connected to the common gnd plane.

    Are all of the eight Vxxxx pins close to 3.3v ?

    Another thing... if you have an inline USB power monitor, check the voltage and current readings when powering from either P2-EVAL USB port.

  • :smh: Would have tried a new cable but those are hard to come by around here. I must be on the bleeding edge of USB-c adoption. Finally dug one up, seems to work, but no idea of its age or condition. I'm going to order a fresh one.

  • Wuerfel_21Wuerfel_21 Posts: 3,402
    edited 2023-01-21 15:58

    Do note that there are two USB ports for a reason. Ideally you should connect the AUX port to a charger of some sort to give the board a solid power supply. If you only use the PC connection, the eval board IME will reset at random times under load.

  • Yeah, I really wish everything was USB-C now. USB Micro-B is just terrible to use as a power connector. When the kids all got devices that use USB-C, I quit having to buy replacement cables and quit using the rework station to replace connectors on their devices.

  • @Wuerfel_21 said:
    Do note that there are two USB ports for a reason. Ideally you should connect the AUX port to a charger of some sort to give the board a solid power supply. If you only use the PC connection, the eval board IME will reset at random times under load.

    Good to know, thanks. What's the story on the Discord server?

  • @expElec said:
    What's the story on the Discord server?

    It exists. Join if you want. Not too populated, but oh well.

  • Hmm, next hurdle: Any suggestions for getting the board recognized on linux (PopOS, Ubuntu style)? Flexprop just says "Could not find a P2 on port /dev/ttyUSB0"

    Unplug / plug cycles show this via dmesg:

    [73244.595947] ftdi_sio ttyUSB0: FTDI USB Serial Device converter now disconnected from ttyUSB0
    [96941.165037] usb 3-3.1: FTDI USB Serial Device converter now attached to ttyUSB0
    [97332.915886] ftdi_sio ttyUSB0: FTDI USB Serial Device converter now disconnected from ttyUSB0
    [97337.721662] usb 3-3.1: FTDI USB Serial Device converter now attached to ttyUSB0

  • Try removing the SD card if you have one inserted.

    If not, check the DIP switches. Set such that USBRES and P59△ are ON and everything else is OFF, this forces serial boot with 60 second timeout.

  • evanhevanh Posts: 14,038
    edited 2023-01-22 03:29

    Check $ groups for you being in dialout group to access the serial ports.

    PS: Assuming you need to add yourself, with a $ sudo usermod -a -G dialout [username], you'll then need to logout to refresh your operating user login config.

  • @evanh said:
    Check $ groups for you being in dialout group to access the serial ports.

    PS: Assuming you need to add yourself, with a $ sudo usermod -a -G dialout [username], you'll then need to logout to refresh your operating user login config.

    Bingo! Blinking LED test is working. Thanks.

  • evanhevanh Posts: 14,038

    Yay.

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