The XBC, or the Xport Botball Controller, is a robot based on Charmed Labs' Xport hardware. It was built specifically for the Botball

Botball

Botball is an educational robotics program that focuses on engaging middle and high school aged students in team-oriented robotics competitions. Thousands of children and young adults participate in Botball’s program...

 competition and uses a Game Boy Advance

Game Boy Advance

The is a 32-bit handheld video game console developed, manufactured, and marketed by Nintendo. It is the successor to the Game Boy Color. It was released in Japan on March 21, 2001; in North America on June 11, 2001; in Australia and Europe on June 22, 2001; and in the People's Republic of China...

 for its display and for high-level processing; a Field-Programmable Gate Array

Field-programmable gate array

A field-programmable gate array is an integrated circuit designed to be configured by the customer or designer after manufacturing—hence "field-programmable"...

 is used to offload low-level processing of motors and sensors from the Game Boy Advance. The XBC is programmed using Interactive C, which is a variant of the C programming language

C (programming language)

C is a general-purpose computer programming language developed between 1969 and 1973 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system....

. The XBC replaced the RCX in 2005 as Botball's official processor. The RCX can be programmed using Interactive C, Not Quite C, or Lego's simple GUI interface. Both robots can have bases built with Lego

Lego

Lego is a line of construction toys manufactured by the Lego Group, a privately held company based in Billund, Denmark. The company's flagship product, Lego, consists of colorful interlocking plastic bricks and an accompanying array of gears, minifigures and various other parts...

pieces.

Sensors

The XBC has ports for LEDs/light sensors, IR reflection/color sensors, SONAR, and touch sensors. A camera can also be connected via a header pin array on the front of the XBC; it can blob-track or serve as a color sensor. The camera's live feed can be displayed on the GBA's screen.

Servos and Motors

The XBC has 4 motor ports and 4 servo ports, each labeled 0-3, respectively. Each motor can be independently programmed to go either backwards or forwards and each servo can be independently changed and controlled with precision. Servos and motors are powered by a separate battery pack from the Game Boy Advance.

Programming

The XBC can be programmed using either Interactive C (IC) or the Xport Development Kit (Xport DK). IC is a simplified variant of C, which is intended to be as easy as possible to use. The Xport DK, in contrast, is a full-blown C/C++ cross-compiler. IC has many feature limitations that are not present in the Xport DK; this is in part a result of the fact that IC was originally written for the Handy Board (which had much fewer features), not the XBC. Some limitations of IC include a 16KiB compiled program size limit, and the lack of features for graphics and sound. The Xport DK was originally designed to program the Xport Robot Controller (XRC - the predecessor of the XBC), and supports the XBC as well. The Xport DK does not have the same limitations of IC, but has its own problem - an almost complete lack of documentation. Because IC is significantly easier to use, has extensive documentation for most features, and is still powerful enough for most uses, the vast majority of XBC users program in IC.

External links

• Charmed Lab's Xport
• Interactive C