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Inside the Handy CricketFred Martin

fredm@handyboard.com

Overview

• Origins and Status of CricketTechnology

• Cricket Hardware• Cricket Firmware and Compiler• Cricket Bus

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Origins and Status• Developed by Brian Silverman and Fred

Martin at MIT Media Laboratory• Have license to all code, designs up to

Aug 2000• Through Gleason Research, distributing

Handy Crickets & more• Publishing APIs• MIT continuing work as well

Handy Cricket Chip BlockDiagram

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The Handy Cricket

2 DC MotorOutputs

2 SensorInputs

Run/Stop Button& LED

2 Bus PortsPiezoBeeper

IR Comms

PowerSwitch 4Kbyte Memory

Cricket Software

• Virtual Machine resident in Cricket Chip(written in PIC assembly)

• Logo compiler running on workstation(written in Java)

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Cricket Logo Compiler• Translates user

Logo into VMbytecodes

• Interactive“Command Center”

• Buffer for editingand definingprocedures

Cricket Logo VM Primitives

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Compiler Examples

Cricket Bus System

• “One-Wire” comms with 1-master,multiple-slaves protocol

• Send and receive can be easilyimplemented with any micro

• Bundle device-specific driver code withHW in device itself

• Allow arbitrary expansion capability

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Handy Cricket Bus Jack

Bus Signal

• Long start bit allows receiver to sync• Data bits just 10 µs long• 9th bit indicates command or data

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4-Digit LED Display

4-Digit Bus Protocol

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Logo Driver Code for Display

“Gama Dome” Block Diagram

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Concluding Remarks

• Cricket system is Cricket + Software +Bus Devices

• Modular and expandable tool thatallows iterative design

• Open for others’ contributions andadaptions

• Not just for roboticists