This is the Revision A verion of the AIROD4 RoboBrick. The status of this project is work in progress.

AIROD4 Robobrick (Revision A)

Table of Contents

This document is also available in PDF format.

1. Introduction

The AIROD4 RoboBrick is used to connect up to 2 Sharp® GP2D12 IROD (InfraRed Optical Distance) measuring sensors. The GP2D12 module provides an analog voltage that is proportional to the distance (although not linearly.)

2. Programming

The AIROD4 RoboBrick is continuously reading the analog inputs from its two AIROD's. The controlling program can just read the results of the digital conversion, or it can have the result down converted into a single binary bit. Each pin has has a threshold high and threshold low register that is used for the down conversion. Whenever the digital conversion exceeds the high threshold register, the down coversion results in a 1. Whenever the digital conversion is lower than the low threshold register, the down conversion results in a 0. A hysterisis effect can be introduced by having some spread between the high and low threshold values.

After the down coversions to binary bits, the result is 2-bits of binary data. A complement mask can be used to selectively invert individual bits in the 2-bit data.

The AIROD4 RoboBrick supports RoboBrick Interrupt Protocol for those lines that are being used as inputs. The interrupt pending bit is set whenever the the formula:

L&(~I) | H&I | R&(~P)&I | F&P&(~I)
is non-zero, where: and Once the interrupt pending bit is set, it must be explicitly cleared by the user.

In addition to the common shared commands and the shared interrupt commands, the AnalogIn4 RoboBrick supports following commands:
Command Send/
Receive
Byte Value Discussion
7 6 5 4 3 2 1 0
Read Distance Send 0 0 0 0 0 0 0 b Read IROD b and respond with 8-bit value dddddddd
Send d d d d d d d d
Read Binary Values Send 0 0 0 0 0 0 1 0 Return the binary values ab (after XOR'ing with complement mask)
Receive 0 0 0 0 0 0 a b
Read Raw Binary Send 0 0 0 0 0 0 1 1 Return the raw binary values ab (no XOR with complement mask)
Receive 0 0 0 0 0 0 a b
Reset Send 0 0 0 0 0 1 0 0 Reset everything to zero
Read Enable Bit Send 0 0 0 0 0 1 0 1 Read and return the enable bit e
Receive 0 0 0 0 0 0 0 e
Set Enable Bit Send 0 0 0 0 0 1 1 e Set enable bit to e
Read Complement Mask Send 0 0 0 0 1 0 0 0 Return and return the complement mask cccc
Receive 0 0 0 0 0 0 c c
Read High Mask Send 0 0 0 0 1 0 0 1 Return and return the high mask hh
Receive 0 0 0 0 0 0 h h
Read Low Mask Send 0 0 0 0 1 0 1 0 Return and return the low mask ll
Receive 0 0 0 0 0 0 l l
Read Raising Mask Send 0 0 0 0 1 0 1 1 Return and return the raising mask rr
Receive 0 0 0 0 0 0 r r
Read Falling Mask Send 0 0 0 0 1 1 0 0 Return and return the falling mask ff
Receive 0 0 0 0 0 0 f f
Read High Threshold Send 0 0 0 1 0 0 0 b Read and return high threshold for pin b of hhhhhhhh
Receive h h h h h h h h
Read Low Threshold Send 0 0 0 1 0 0 1 b Read and return low threshold for pin bb of llllllll
Receive l l l l l l l l
Set High Threshold Send 0 0 0 1 0 1 0 b Set high threshold for pin b to hhhhhhhh
Send h h h h h h h h
Set Low Threshold Send 0 0 0 1 0 1 1 b Set low threshold for pin b to llllllll
Send l l l l l l l l
Set Complement Mask Send 0 0 1 0 0 0 c c Set complement mask to cc
Set High Mask Send 0 0 1 0 0 1 h h Set high mask to hh
Set Low Mask Send 0 0 1 0 1 0 l l Set low mask to ll
Set Raising Mask Send 0 0 1 0 1 1 r r Set raising mask to rr
Set Falling Mask Send 0 0 1 1 0 0 f f Set falling mask to ff
Read Interrupt Bits Send 1 1 1 0 1 1 1 1 Return the interrupt pending bit p and the interrupt enable bit e.
Receive 0 0 0 0 0 0 e p
Set Interrupt Commands Send 1 1 1 1 0 c c c Set Interrupt Command ccc.
Shared Commands Send 1 1 1 1 1 c c c Execute common shared command ccc

3. Hardware

The hardware consists of a circuit schematic and a printed circuit board.

3.1 Circuit Schematic

The schematic for the AIROD4 RoboBrick is shown below:

AIROD4 Schematic

The parts list kept in a separate file -- airod4.ptl.

3.2 Printed Circuit Board

The printed circuit board files are listed below:

airod4_back.png
The solder side layer.
airod4_front.png
The component side layer.
airod4_artwork.png
The artwork layer.
airod4.gbl
The RS-272X "Gerber" back (solder side) layer.
airod4.gtl
The RS-272X "Gerber" top (component side) layer.
airod4.gal
The RS-272X "Gerber" artwork layer.
airod4.drl
The "Excellon" NC drill file.
airod4.tol
The "Excellon" tool rack file.

4. Software

The software for the AIROD4 is listed below:

airod4.ucl
The µCL file for AIROD4.
airod4.asm
The assembly file for AIROD4.
airod4.hex
The Intel® Hex file.
airod4.lst
The listing file for AIROD4.

5. Issues

The following fabrication issues have come up:


Copyright (c) 2001-2002 by Wayne C. Gramlich. All rights reserved.