Handy Board FAQ Answers: “mbdiff”
How can I choose between the Handy Board and the Mini Board?
First, lots of people use Mini Boards. There are more than 2000 of them out in the world.But when deciding if the Mini Board is what you need, keep in mind its main constraint: no memory external to the 6811 chip. The 6811 recommended for use with the Mini Board (the mc68hc11e2fn) has 2048 bytes of EEPROM program memory (and 256 bytes of RAM).
In practice, this means that programming the Mini Board is best done in assembly language or a traditional compile-link-download version of C (like Dunfield's Micro-C or ImageCraft C). The Mini Board cannot run Interactive C, because Interactive C requires 32K of RAM memory.
So this means that programs running on the Mini Board are necessarily small. If the application is one with a particular dedicated functionality, that is often fine, and the Mini Board's small size and low cost are advantages. Or, if the application is connecting motors and sensors to a desktop computer, the Mini Board is a great solution as a "serial line slave" interface.
The other virtue of the Mini Board is its simplicity. It has only 4 chips and is easy to build. The core features of a 6811 with 2048 bytes of memory, 4 DC motor outputs, 8 analog inputs, and 8 digital I/O pins make it suitable for many robotic applications.
On the other hand, If the application is more open-ended and experimental, and cost is not an extreme limiting factor, the Handy Board is a more satisfactory choice. In a board about twice the area of the Mini Board, it provides the additional features of 32K of battery-protected static RAM memory, an LCD screen, infrared decoder chip, infrared output oscillator, battery charge circuitry, a piezo beeper, and a user knob.
For experimental and educational purposes, the Handy Board's capability to run Interactive C is the distinguishing difference. Also, the LCD screen is great for remote interpretation of sensor data and general debugging purposes.
For information on the Mini Board is available from ftp://cherupakha.media.mit.edu/pub/projects/miniboard/gen-info.txt.
The Handy Board home page is located at http://handyboard.com/.
(Last updated 2000-09-26)