Raspberry Pi RoboPi User Manual

Using RoboPi

RoboPi User Manual v0.60

The most up to date documentation will always be available at:

http://www.mikronauts.com/raspberry-pi/robopi/

http://Mikronauts.com 1 2014-01-27

Photo 1: Fully assembled RoboPi v1.00

Table of Contents

Introduction................................................................................................................................................3

RoboPi Printed Circuit Board....................................................................................................................4

RoboPi I/O Pin Definitions........................................................................................................................5

P0-P7: SERVO 1 – SERVO 8................................................................................................................5

P8-P15: SERVO 9 – SERVO 16............................................................................................................5

P16-P23: SENSOR 1 – SENSOR 8......................................................................................................5

P24-P27: SPI port for MCP3008/MCP3208.........................................................................................5

ADC1-ADC8: 0-5V Analog inputs.......................................................................................................5

Programming RoboPi with RoboPiLib......................................................................................................6

Using the Raspberry Pi serial port with RoboPi....................................................................................6

RoboPiLib Constants.............................................................................................................................7

RoboPiLib Functions.............................................................................................................................7

Programming RoboPi with RoboPiObj......................................................................................................8

RoboPiObj Constants............................................................................................................................8

RoboPiObj Methods..............................................................................................................................8

RoboPiObj Resource Utilization...........................................................................................................8

How to use Digital Inputs..........................................................................................................................9

Reading Bumper Switches....................................................................................................................9

How to use Digital Outputs......................................................................................................................10

Using LED's to show which bumper is pressed..................................................................................10

How to use Servos....................................................................................................................................11

Controlling a Continuous Rotation Servo...........................................................................................11

Controlling a Standard Servo..............................................................................................................11

How to use PWM to control Gear Motors...............................................................................................12

EN/A/B Three Wire Driver.................................................................................................................12

A/B Two Wire interface.......................................................................................................................12

EN/DIR/PWM Three Wire Driver.......................................................................................................13

DIR/PWM Two Wire Driver...............................................................................................................13

Why the ENABLE signal of three wire drivers is useful....................................................................13

Reading Analog Distance Sensors...........................................................................................................14

Reading Digital Ultrasonic Range Sensors..............................................................................................15

Ultrasonic Sensors to be supported:....................................................................................................15

Stand-Alone Operation............................................................................................................................16

Appendix A: Software..............................................................................................................................17

Appendix B: Data Sheets.........................................................................................................................17

Appendix C: Support...............................................................................................................................17

Appendix D: RoboProp Software Compatibility:....................................................................................18

Appendix E: Frequently Asked Questions...............................................................................................19

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Introduction

RoboPi is the most advanced robot controller add-on board for the Raspberry Pi available at this time. RoboPi adds an eight-core 32-bit microcontroller running at 100Mhz to the Raspberry Pi in order to off-load hard real time I/O and allow more precise timing than Linux running on the Pi allows.

RoboPi stacked on top of a Model A Raspberry Pi

RoboPi can also be stacked on top of Model B Raspberry Pi's

RoboPi Features

• Parallax Propeller P8X32 eight core 32 bit Risc microcontroller running at 100Mhz

• Each of the eight cores provides up to 25MIPS as most instructions take only 4 clock cycles

• three ten-pin Mikronauts I/O module expansion connectors (P0-P7, P8-P15, P16-P23)

• 24 servo compatible headers on P0..P23

◦ P0-P7 jumper selectable power from Pi's 5VDC supply or external servo power supply ◦ P8-P15 jumper selectable power from Pi's 5VDC supply or external servo power supply ◦ P16-P23 is powered by 5V from the Pi expansion header for sensors

• Screw terminal for providing external power for Servo connectors P0-P15

• 8 servo compatible headers for an eight channel 0-5V analog to digital converter with choice of

◦ MCP3008 for 10 bit A/D conversion ◦ MCP3208 for 12 bit A/D conversion

• Choice of 256Kbit or 512Kbit boot EEPROM for the Propeller

• On-board voltage regulation providing 3.3V with power on LED from the 5V on the Pi header

• 4 pin I2C expansion header for the Raspberry Pi

• 4 pin I2C expansion header for the Propeller

• 5 pin HCOM connector for use with PropPlug in stand alone operation (optional)

• Mikronauts EZasPi prototyping board can stack below RoboPi

• Mikronauts Pi Jumper can stack on top of RoboPi

• Mikronauts SchoolBoard ][ and other Propeller products are compatible with RoboPi

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RoboPi Printed Circuit Board

Here is a top view of where parts are located on the RoboPi printed circuit board:

You can refer to this image while wiring your robot after assembling your RoboPi.

PLEASE NOTE

The “PROPPLUG” connection is for stand-alone RoboPi operation (where RoboPi is NOT stacked on top of a Raspberry Pi. Pins 1-4 are the same as PropPlug (Pin 1 is GND), Pin 5 adds 3.3V for SerPlug.

Plugging in a PropPlug while RoboPi is stacked on the Raspberry Pi may damage your Raspberry Pi and/or RoboPi.

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RoboPi I/O Pin Definitions

Before you can write programs for your RoboPi based robot, you have to learn what resources are available for you to connect to sensors, motors and other devices or boards.

P0-P7: SERVO 1 – SERVO 8

• 10 pin EXP1 connector connected directly to processor pins, 3v3 I/O only

• connects to signal pin on SERVO1-8 through a 2k4 current limiting resistor, 5V I/O safe

• For the servo header, SV2 selects between the Pi's 5V and VBat from the screw terminal

P8-P15: SERVO 9 – SERVO 16

• 10 pin EXP2 connector connected directly to processor pins, 3v3 I/O only

• connects to signal pin on SERVO9-16 through a 2k4 current limiting resistor, 5V I/O safe

• For the servo header, SV3 selects between the Pi's 5V and VBat from the screw terminal

P16-P23: SENSOR 1 – SENSOR 8

• 10 pin EXP3 connector connected directly to processor pins, 3v3 I/O only

• connects to signal pin on SENSOR1-8 through a 2k4 current limiting resistor, 5V I/O safe

• the Pi's 5V is used for SENSOR1-8 to provide cleaner power to Ping's etc

P24-P27: SPI port for MCP3008/MCP3208

• P24 is MISO, connected to DO on ADC through a 2k4 current limiting resistor

• P25 is MOSI

• P26 is CLK

• P27 is /CS

ADC1-ADC8: 0-5V Analog inputs

• connects to the signal pin on ADC1-8 servo style header

• the Pi's 5V is used for ADC1-8 to provide cleaner power to Ping's etc

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Programming RoboPi with RoboPiLib

Using the Raspberry Pi serial port with RoboPi

The Raspberry Pi has 3.3V serial RX and TX signals available on its 26 pin header.

Normally this port is configured to display boot messages, after which it becomes a serial console.

My favorite small text editor is 'joe', which you can install with

sudo apt-get install joe

then

sudo joe /boot/cmdline.txt

remove “console=ttyAMA0, 115200 kgdboc=ttyAMA0, 115200”

sudo joe /etc/inittab

Find the line

T0:23:respawn:/sbin/getty -L ttyAMA0 115200 vt100

and insert a '#' in front of T0:23

For the changes to take effect, type

sudo shutdown now -r

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+ 13 hidden pages

Raspberry Pi RoboPi User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual