UBW Project Overview

Summary:
UBW stands for USB Bit Whacker. It is a series of boards and software that allow people to do real-world interfacing from their PCs. The boards are very simple, cheap, and generic. The whole design is free to anybody to use and do anything they want with, including commercially produce these boards or derivative works. All software tools used are free, and all code is provided with documetnation so you can take one of the examples on this website and change it to do whatever you want.

Who Cares:
There are three classes of people who may like the UBW design:

People who just want to use an existing board and firmware to get some real work done (i.e. parallel port replacement, education, etc.)
People who want to use an existing board but write their own firmware
People who want to build a UBW from scratch and the use existing firmware or write their own

Depending upon what you plan to do you will want to read certain web pages here and not others.

Example Projects using UBW:

Simple parallel port replacement for moving stepper motors under PC application control
Simple USB<->RS-232, USB<->I2C, USB<->SPI bridge, possibly with custom software to 'modify' bytes as they flow back and forth
Simple data logger (UBW has analog inputs and digital I/O)
Step and direction timing generator for complex motion paths using stepper motors
Microcontroller educational tool
JTAG programmer, digital pattern generator, simple oscilloscope and logic analyzer

Has anyone done this before?
Sure. Sort of.

The C.R.E.A.T.E. USB Interface is probably the closest that I know about. Note the similarity in schematic! I took much of my inspiration from their design. The big difference? Mainly that their software shows up as a HID (Human Interface Device - like a keyboard, mouse, joystick) device on your computer rather than a virtual serial port. This limits their bandwidth to the PC, but means there are never any speical drivers or installation headaches. Also, I don't believe they use a USB bootloader, and they only have a 44 pin PIC part, not the 28 pin version we have. Thus their design is a bit more expensive to produce.
Very similar in nature is the Arduino board which is a totally slick product. Much larger following than CREATE or UBW espically in Europe. Instead of using a USB capable processor, they tie a USB to serial converter chip to the USART on an Atmel processor. How their system works is by having a custom PC application that is an editor for code, a compiler, and a downloader all in one. When you hit 'download' it compiles your code and the downloads it to the Atmel's flash. So the Arduino is set up out of the box to run stand-alone, unlike the UBW where you have to write your own firmware version if you want the UBW to do something spcial without a PC. (Not hard, but not as easy as with Arduino) The language they impliment is called Processing/Wiring which is pretty neat, but it's not C or BASIC, so you need to learn how to use their libaries. The always awesome SparkFun carries both the Arduino and its larger brother the Wiring board.

Board details:
There will eventually be at least four boards, one for each package type that the Microchip USB PICs come in. Each board has different uses, but the same basic software can run on all four boards.

28-pin DIP Board : Uses a PIC18F2455 or PIC18F2550 processor. 19 free I/O pins.
28-pin SOIC Board : Uses a PIC18F2455 or PIC18F2550 processor. 19 free I/O pins.
40-pin PDIP Board : Uses a PIC18F4455 or PIC18F4550 processor.
44-pin TQFP Board : Uses a PIC18F4455 or PIC18F4550 processor.
44-pin QFN Board : Uses a PIC18F4455 or PIC18F4550 processor.

Software Details:
The boards are designed to be used with a slightly modified version of Microchip's USB bootloader so that you don't need any extra hardware to re-program the boards with new firmware, just a PC and a USB port. The boards can be used without the bootloader if you want, as the ICSP pins are brought out to a header and thus the boards can be programmed with any PIC programmer capible of programming these 18F parts. However, all software examples on this website are designed to work with the bootloader.

There are several versions of 'application' firmware that have already been developed, and more are on the way. I have labeled them with single letters. The firmware applications and bootloader code is all developed in Microchip's MPLAB IDE, using their Student Edition of their C18 compiler. All firmware versions are based off of Microchip's sample USB code, without which this project never would have happend. Thank you Microchip!

Each of the different firmware versions (or builds) has some different purpose. This web site provides pre-built versions of each firmware build, so if all you want is the basic functionality of the build, all you have to do is use the build-in USB bootloader and download the firmware you want to use and run with it! If, however, you want to do something different, you can use any of the existing firmware builds here and roll your own to do whatever you want.

USB Bootloader (firmware B) : A slightly modifed version of Microchip's USB bootloader. Use it to download other firmware to your UBW.
Simple CDC application (firmware C) : UBW appears as a virtual COM port. Each byte you write to that COM port appears on port B of the UBW.
Advanced CDC application (firmware D) : UBW appears as virtual COM port. Extended commands allow reading/writing each I/O pin, A/D conversions, etc.
Custom Stepper Controller (firmware S) : UBW appears as virtual COM port. Command packets cause UBW to generate step and direction pulses on port B for four stepper motors.

Questions? E-mail me at my e-mail address

Back to main UBW page