WEB-BASED LEARNING TOOLS ON MICROPROCESSOR FUNDAMENTALS FOR A FIRST-YEAR ENGINEERING COURSE

ByJucain Butler

Outline of Presentation

Introduction Demo Student Responses Inside the Simulator Conclusion

Introduction

WWW has changed how teaching occurs

Virtual labs limited resources physical space restrictions

The Tutorial A series of surveys, quizzes, references

and interactive programs that simulates how a computer based on Feynman’s File Clerk and one based on the LEGO RCX executes a program.

Previous Work

Seymour Papert at MIT -- LOGO Fred Martin at MIT - programmable brick CEEO at Tufts – K-12 education Dave Baum of Motorola – NQC Richard Feynman – Lectures on Computation

What is the RCX

3 input Sensors

3 output Motors

•32 16-bit registers•datalog•Virtual machine•Infrared transceiver•programmable in NQC

Maxfinder

Developed web-based tutorial to enable students to understand what goes on internally in a computer for program like the maxfinder

Developed web-based tutorial to enable students to understand what goes on internally in a computer for program like the maxfinder

How students proceed through the tutorial

Pre-survey

Read reference page

Post-survey

Interactive demoW/ simulator

Take quiz

Arithmetic Operations Reference Page -- RCX

1. The first byte represents one of five operations.1)     14 (setv)- stores a value in the destination register2)     24 (sumv)- adds operand 1 to operand 2 3)     34 (subv)- subtracts operand 2 from operand 14)     44 (divv)- divides operand 2 into operand 15)     54 (mulv)- multiplies operand 1 to operand 2 

2. The second byte is the index (or register number) of the register that holds operand 1 and is the index of the destination register that stores the result. 

3. The third byte represents one of three types for operand 2.1)         0 – the value of operand 2 is stored in a variable register2)         2 – the value of op 2 is immediately provided by the next two bytes3)         9 – the value of operand 2 is provided by a sensor 

4. The fourth byte is the least significant byte of argument to the second operand. 

5. The fifth byte is the most significant byte of argument to the second operand. (Note that the last two bytes combine to form a two byte integer that together represent the argument to the second operand.  

Arithmetic Operations Reference Page -- RCX

Assembly Operation Machine code

sum v[0], v[2] v[0] = v[0] + v[2] 24 00 00 02 00

set v[2],0x1A5 V[2] = 0x1A5 14 02 02 A5 01

set v[7], input(1)A V[7]=sensor val port1

14 07 09 01 00

Arithmetic Operations Reference Page -- FC

1. The first byte represents one of three operations.

1)     14 (input)- input value from the scrollbar into the register2) 21 (output)- output the value from the register to the screen 3) 24 (add)- add contents of first register to the second4)     34 (sub)- subtract contents of first register from second5)     44 (div)- divide contents of second register into the first6)     54 (mult)- multiply contents of first register by the second

2. The second byte is the index (or register number) of the register that holds operand 1 and is the index of the destination register that stores the result. 

3. The third byte represents the second operand.

Arithmetic Operations Reference Page-- FC

Instruction Operation Machine code

add v[0], v[2] v[0] = v[0] + v[2] 24 00 02

input v[2] V[2] = input value Input 2

mult v[9], v[10] V[9] = v[9] x v[10] 54 09 10

Proceed to demo

DEMO

Quotes from Student Responses

“It was useful in understanding the underlying task the RCX performs to process our NQC commands.”

“It was very helpful, and I believe we should have been required to do this before the Scanner project.

“I wish that more resources like these were made available throughout the entire EG 111/112 course. They are an excellent supplement to the course and provide instruction where the course is lacking.”

Quotes from Student Responses cont’d

“I found it interesting to see how high-level code works as machine code.”

“ I was confused by some of the terminology and it would have been helpful to have someone there to explain.”

Quotes from Student Responses cont’d

“I think that the online tutorial is a useful tool but could become overused by professors. This may lead to excessive information for the students, and the professors not teaching.”

RCXSimulator

Display GUIs/Externals

State/Internals

Controlbuttons

Displaywindows

Section headings

Register &I/O Device

state

Executionstate

Program code

Motorstate

Sensorstate

programcounter

Registers Instructionset

Extra storage

Simulator Organization

Boxes correspondTo major classesIn Java applet

RCXSimulator Class

accept a program, step or run through the execution of that program, and displaying the state

an abstract class that inherits from the APPLET class

important methods

init ()  - initialize variables and instantiate instances of major & GUI classes

run() - if the run button is pushed, execute the next instruction until the end

actionPerformed() - perform function based on which control button is selected

abstract int[] getTheProgram() - get the array of bytecodes

Conclusions – major contributions

An effective online tutorial with simulator using WebCT

A simulator for the RCX

Impacted the education of 300 students

Conclusions - Findings

Effective as indicated by quiz & survey results

Useful as a supplement to an introductory engineering course

Some aspects are too technical

Future Work

Future Increase functionality A model approach to other Domains

Chemical Engineering Nano Technology

File Clerk Simulator

RCX Simulator