robot building lab: introduction lab 1 the handy board and interactive-c (ic) ...
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Robot Building Lab: Introduction
Lab 1
The Handy Board and Interactive-C (IC)
http://plan.mcs.drexel.edu/courses/robotlab/labs/lab1.ps
Robot Building Lab: Introduction
Purpose
Introduce the Handy Board micro-controller
Introduce IC programming languageWrite simple control program in IC
Robot Building Lab: Introduction
Handy BoardMotorola 6811 microprocessor, 2
MHz. 32K of static RAM. ability to drive 4 DC motors. 16 x 2 character LCD screen. 2 programmable buttons, one
knob, and piezo beeper.inputs for 7 analog sensors and
9 digital sensors.9.6v nicad battery with
recharging circuit.8-pin serial connectorPlus more …
(copyright Prentice Hall 2001)
Robot Building Lab: Introduction
Attaching Motors and Sensors
(copyright Prentice Hall 2001)
Robot Building Lab: Introduction
Connecting PC to HB
Robot Building Lab: Introduction
Serial Line Circuit HB communicates with host
computer over RS-232 serial line
Serial Interface/Battery Charger board performs voltage conversion
Connecting Handy Board
(copyright Prentice Hall 2001)
Robot Building Lab: Introduction
Interactive-CVery similar to C (subset)
void main(void) { printf("Press start!\n"); start_press(); while (!stop_button()) { if (analog(0) > analog(1)) { motor(1, 0); motor(0, 50); } else { motor(0, 0); motor(1, 50); } } ao();/* end main */}What does this program do?
Robot Building Lab: Introduction
Brief Introduction to Programming in Interactive-C Interactively
– C> 1+2;– C> {start_press(); motor(0,50); stop_press();
ao();}
Downloading- write a function – “main” is the default- Download to Handy Board- Execute main()- Main() automatically executed on power up
- (unless you press “start” or “stop” (re-load pcode) during power up)
Robot Building Lab: Introduction
Interactive C Features Interactive experimentation Compiled into P-code (pseudo-code) P-code interpreted by run-time machine
language program on Handy Board Built-in multi-tasking Built-in libraries to access Handy Board
hardware – sensor inputs, motor outputs, etc Additional features: persistent global variables,
built-in math functions, character arrays but no chars, one-dimensional arrays (multi-dimensional in some versions)
Robot Building Lab: Introduction
DC Motor Output Commands
void motor(int m, int p)– Turns on the motor in port m– And runs the motor with power level p -- full
forward = 100, full backward = -100 (using pulse-width modulation)
void off(int m)– Turns off motor m.
void alloff(), void ao()– Turns off all motors
Robot Building Lab: Introduction
Sensor Input Commands
int digital(int p)– Returns the value of the sensor in sensor
port p, as a true/false value (1 for true and 0 for false).
int analog(int p)– Returns value of sensor port numbered p.
Result is integer between 0 and 255.
Ports are numbered as marked on Handy Board
Robot Building Lab: Introduction
Seeking/Avoiding Light
Motor(left_motor, left_light);
Motor(right_motor, right_light);
if (analog(left_light) <= light_thresh) motor(left, minimal_power);
(From Braitenberg)
Robot Building Lab: Introduction
Buttons and Knob Inputs
int stop_button()– Returns value of button labeled STOP: 1 if
pressed and 0 if released.
int start_button()– Returns value of button labeled START.
int knob()– Returns the position of a knob as a value
from 0 to 255.
Robot Building Lab: Introduction
Example pressing buttons program
void main(void) { printf("Press start!\n"); start_press();
motor(0, 50); stop_press();
ao();/* end main */}
Robot Building Lab: Introduction
Example If-else
void main(void) { printf("Press start!\n"); start_press(); if (analog(0) > analog(1)) { motor(0, 50); } else { motor(1, 50); } stop_press(); ao();/* end main */}
Robot Building Lab: Introduction
Example While Loop
void main(void) { printf("Press start!\n"); start_press(); while (!stop_button()) {
motor(0,50);}
ao();/* end main */}
Robot Building Lab: Introduction
Light demo/* lightdemo.c - [email protected] */void main(void) { printf("Press start!\n"); start_press(); while (!stop_button()) { if (analog(0) > analog(1)) { motor(1, 0); motor(0, 50); } else { motor(0, 0); motor(1, 50); } } ao();/* end main */}
Robot Building Lab: Introduction
Miscellaneous Commands
void sleep(float sec)– Waits for an amount of time equal to or slightly
greater than sec seconds. void msleep(long msec)
– Waits for an amount of time equal to or greater than msec milliseconds.
void beep()– Produces a tone of 500 Hertz for a period of 0.3
seconds. Math lib: sin, cos, tan, atan, sqrt, log10, log, exp10, exp,
^ 6811 machine language programs may be called
Robot Building Lab: Introduction
Multi-tasking Overview Processes can be created and destroyed dynamically
during run-time. Any C function can be spawned as a separate task. Processes communicate through global variables. Each time a process runs, it executes for a certain
number of ticks. All processes are kept track of in a process table; each
time through the table, each process runs once (for an amount of time equal to its number of ticks).
When a process is created, it is assigned a unique process identification number or pid. This number can be used to kill a process.
Robot Building Lab: Introduction
Multi-tasking Commands int start_process( function-call(: :) ,[TICKS],[STACK-
SIZE])– start process returns an integer, which is the process ID
assigned to the new process. int kill_process(int pid)
– kill process returns a value indicating if the operation was successful.
void hog_processor()– Allocates an additional 256 milliseconds of execution to the
currently running process. void defer()
– Makes a process swap out immediately after the function is called.
IC commands– Kill_all -- kills all currently running processes.– Ps -- prints out a list of the process status.
Robot Building Lab: Introduction
Programming Tips
32K of RAM includes p-code interpreter and C libraries and program stack
Reduce redundant code by using functions
Comments don’t take up RAMWrite simple behaviors and then focus
on how to coordinate them rather than trying to write one big encompassing behavior
Robot Building Lab: Introduction
Next Week Read on-line documents and answer questions
specified at http://plan.mcs.drexel.edu/robotlab/questions/question1.ps
Teams will be determined based on next week’s attendance
Lab 2: Structures and Drivetrains Lab fee ($50) and deposit ($50) due: Bring check
payable to “Drexel University” for $100. In memo field put “CS 280/680 Lab Fee/Deposit”
Sign up for class mailing list:– Send mail to [email protected] from your
desired email account, – with no subject and – the body “subscribe robotlab”
Robot Building Lab: Introduction
Lab 1: The Handy Board and Interactive-C (IC)
Files:– http://plan.mcs.drexel.edu/courses/robotlab/labs/lab1.
pdf– http://plan.mcs.drexel.edu/projects/legorobots/
handyboard.html– http://plan.mcs.drexel.edu/courses/robotlab/readings/h
bmanual.pdf Lab overview:
– Connect HB to computer– Download IC, Start IC, experiment with command line
programming– Write and download programs to HB
• Print to LCD screen, using buttons, knob and loops to vary output• Control motor using knobs and buttons• Write motor experimentation program, parameterized by port,
allowing the user to run a motor at differing speeds/directions for differing durations
– Test program untethered