This is the Revision B verion of the Birod4 RoboBrick. The status of this project that it has been replaced by the BIROD5 RoboBrick.

BIROD2 Robobrick (Revision B)

This document is also available as a PDF document.

1. Introduction
2. Programming
3. Hardware
- 3.1 Circuit Schematic
- 3.2 Printed Circuit Board
4. Software
5. Issues

1. Introduction

The BIROD2 RoboBrick is used to connect to up to 2 of the Sharp^® GP2D05 IROD (InfraRed Optical Distance) measuring sensors. This version of the Sharp chip provides a single bit of information for when the sensor is within a fixed distance an object.

2. Programming

The basic operation is to send a query to the BIROD2 RoboBrick to read the 2 bits of data. The programmer can download a complement mask to cause any of the bits to be complemented prior to reading.

There is an enable mask that allows the programmer to individually enable and disable one or the other IROD. In addition, there is an alternate bit which, when set, causes the IROD's to be alternately strobed. The alternate bit would be set if you are concerned that one sensor might interfere with another.

The BIROD2 RoboBrick supports RoboBrick Interrupt Protocol. The interrupt pending bit is set whenever the the formula:

L&(~I) | H&I | R&(~P)&I | F&P&(~I)]

is non-zero, where:

I is the current input bits XOR'ed with the complement mask (C)
P is the previous value of I
L is the low mask
H is the high mask
R is the raising mask
F is the falling mask

and

~ is bit-wise complement
| is bit-wise OR
& is bit-wise AND

Once the interrupt pending bit is set, it must be explicitly cleared by the user.

The BIROD2 RoboBrick supports both the standard shared commands and the shared interrupt commands in addition to the following commands:

Command Send/
Receive Byte Value Discussion
7 6 5 4 3 2 1 0
Read Inputs Send 0 0 0 0 0 0 0 0 Return input values ab (after XOR'ing with complement mask)
Receive 0 0 0 0 0 0 a b
Read Raw Send 0 0 0 0 0 0 0 1 Return raw data ab (without XOR'ing with complement mask)
Receive 0 0 0 0 0 0 a b
Read Alternate Bit Send 0 0 0 0 0 0 1 0 Return alternate bit a
Receive 0 0 0 0 0 0 0 a
Read Enable
Complement Mask Send 0 0 0 0 0 0 1 1 Return enable mask ee and complement mask cc
Receive 0 0 0 0 e e c c
Read High
Low Mask Send 0 0 0 0 0 1 0 0 Return high mask hh and low mask ll
Receive 0 0 0 0 h h l l
Read Raising
Falling Mask Send 0 0 0 0 0 1 0 1 Return raising mask rr and falling mask ff
Receive 0 0 0 0 r r f f
Set Alternate Bit Send 0 0 0 0 0 1 1 a Set the alternate bit to a.
Set Enable
Complement Mask Send 0 0 0 1 e e c c Set enable mask to ee and complement mask to cc.
Set High Low Mask Send 0 0 1 0 h h l l Set high mask to hh and low mask to ll.
Set Raising Falling Mask Send 0 0 1 1 r r f f Set raising mask to rr and 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 Bit Commands Send 1 1 1 1 0 c c c Execute shared set interrupt command ccc.
Shared Commands Send 1 1 1 1 1 c c c Execute shared command ccc.

Command	Send/ Receive	Byte Value	Discussion
7	6	5	4	3	2	1	0
Read Inputs	Send	0	0	0	0	0	0	0	0	Return input values ab (after XOR'ing with complement mask)
Receive	0	0	0	0	0	0	a	b
Read Raw	Send	0	0	0	0	0	0	0	1	Return raw data ab (without XOR'ing with complement mask)
Receive	0	0	0	0	0	0	a	b
Read Alternate Bit	Send	0	0	0	0	0	0	1	0	Return alternate bit a
Receive	0	0	0	0	0	0	0	a
Read Enable Complement Mask	Send	0	0	0	0	0	0	1	1	Return enable mask ee and complement mask cc
Receive	0	0	0	0	e	e	c	c
Read High Low Mask	Send	0	0	0	0	0	1	0	0	Return high mask hh and low mask ll
Receive	0	0	0	0	h	h	l	l
Read Raising Falling Mask	Send	0	0	0	0	0	1	0	1	Return raising mask rr and falling mask ff
Receive	0	0	0	0	r	r	f	f
Set Alternate Bit	Send	0	0	0	0	0	1	1	a	Set the alternate bit to a.
Set Enable Complement Mask	Send	0	0	0	1	e	e	c	c	Set enable mask to ee and complement mask to cc.
Set High Low Mask	Send	0	0	1	0	h	h	l	l	Set high mask to hh and low mask to ll.
Set Raising Falling Mask	Send	0	0	1	1	r	r	f	f	Set raising mask to rr and 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 Bit Commands	Send	1	1	1	1	0	c	c	c	Execute shared set interrupt command ccc.
Shared Commands	Send	1	1	1	1	1	c	c	c	Execute 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 Birod2 RoboBrick is shown below:

The parts list kept in a separate file -- birod2.ptl.

The table below provides the color code for connecting Sharp^® GP2D05's to the BIROD2 RoboBrick:

IROD Pin Symbol Wire Color Connect To RoboBrick Pin
1 V_in Green VIN0 or VIN1 2 or 4
2 Ground Black GND 1
3 V_out Blue VOUT0 or VOUT1 3 or 5
4 V_cc Red PWR 6

IROD Pin	Symbol	Wire Color	Connect To	RoboBrick Pin
1	V_in	Green	VIN0 or VIN1	2 or 4
2	Ground	Black	GND	1
3	V_out	Blue	VOUT0 or VOUT1	3 or 5
4	V_cc	Red	PWR	6

3.2 Printed Circuit Board

The available printed circuit boards are listed below:

birod2_back.png: The solder side layer.
birod2_front.png: The component side layer.
birod2_artwork.png: The artwork layer.
birod2.gbl: The RS-274X "Gerber" back (solder side) layer.
birod2.gtl: The RS-274X "Gerber" top (component side) layer.
birod2.gal: The RS-274X "Gerber" artwork layer.
birod2.drl: The "Excellon" NC drill file.
birod2.tol: The "Excellon" NC drill rack file.

4. Software

The BIROD2 software is available as one of:

birod2.ucl: The µCL source file.
birod2.asm: The resulting human readable PIC assembly file.
birod2.lst: The resulting human readable PIC listing file.
birod2.hex: The resulting Intel^® Hex file that can be fed into a PIC12C5xx programmer.

The BIROD2 test software is available as one of:

birod2_test.ucl: The µCL source file.
birod2_test.asm: The resulting human readable PIC assembly file.
birod2_test.lst: The resulting human readable PIC listing file.
birod2_test.hex: The resulting Intel^® Hex file that can be fed into a PIC12C5xx programmer.

5. Issues

The following fabrication issues came up:

The holes in N1 are too large (size 3) and should be made smaller (size 2.)
The label says BIROD2-A instead of BIROD2-B.
Move the labeling of N2 to the left.
Think about trying to build and BIROD3 or BIROD4 using a PIC16C505.
Think about switching over to PIC16C505 and adding a couple of LED's that show the state of each sensor and a couple of LED's that indicate if they are on or not.