USB Interface

The Handy Board has a USB-serial interface for communications with the host computer.

Handy Board USB-Serial Interface
Handy Board USB-Serial Interface Board

The USB Interface has similar features as the original Serial Interface:

  • RJ11 telephone-style cable to connect to Handy Board
  • trickle and rapid charge modes for Handy Board’s built-in nicad battery
  • charge circuit powered by external 12v, 500mA DC adapter

It also provides communications with the Handy Board via the USB connection.  The board has a driver chip from FTDI; download the “VCP” (virtual COM port) driver for your operating system (Windows, Mac, or Linux) from

Here is a schematic of the USB Interface Board. In addition to connecting to the Handy Board’s serial communications lines, the USB board also provides 0.1” headers for connecting to your own TTL-level serial circuit.  Pads for supplying +5v, ground, TxD, and RxD are available.

11 thoughts on “USB Interface”

  1. Please tell me what ports to use for the Optical Rangefinder and for encoders.

    Thanks in advance for your time.

    Pedro A

  2. I have the serial interface with a serial to usb connector connecting it to my windows 7 computer. When I open up IC, it just shows the default com port 1 and nothing else. This is not the right port and I cannot connect to my handy board. I installed the VCP driver but still nothing works. Any thoughts?

  3. It sounds like your USB-serial adapter doesn’t have its driver installed right. Check the System Properties for COM ports; it should show up there. Make sure you have the right driver given the manufacturer of the adapter.

  4. Hello,
    I was wondering what settings you used to the the ftdi232RL to work in bootstrap mode. I have a ftdi usb adapter but I can’t seem to the the timing worked out. Thank you very much.

  5. If I remember correctly, the HC11’s bootloader operates at 1200 baud. But this is all handled by Interactive C and its “download firmware” function. You shouldn’t have to separately set serial parameters, unless you’re writing your own bootloader.

    If you are writing your own bootloader, I have a simple one written in Java. See and look at Assignments 3 and 4.

  6. Running Win7 32bit, the Handy Board USB Interface/Charger is detected, comes up in Device Manager as COM2 (and can be changed to any other availabe COM port,) but does not communicate with Interactive C v8.0.2. However, the older Hander Board Serial works like a champ with a USB to serial adapter.

    Tried the latest drivers from the FTDI site and Microsoft says the drivers from the site are the same as the ones that are already loaded for the device.

    Any suggestions?

    FYI – I’m IT support, but this is the 1st time I ever touched one of these boards or dealt this anything like it. Please respond in laymans terms. Thanks

  7. Chris: Try reinstalling the FTDI drivers from scratch, first removing them with a utility called FTCLEAN. Find FTCLEAN on this page:

    When you run the utility, read the dialog choices closely, it’s a bit confusing and the defaults will cause you to NOT run the program 🙂

    Then reinstall the latest drivers from FTDI and let us know if it works.

  8. Fredm: No luck with your suggestion. More info on the computer itself – Dell Optiplex 960, 4GB, Win7 Pro. Tried on both 32bit and 64bit win7 Pro. Thanks for your suggestion.

  9. Sorry Chris, this should work. Can you try the USB Interface on another machine (e.g., an XP machine) to determine if it’s a HW problem with the interface. Fred.

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