Microcontrollers. What is a Microcontroller. Setting up. Sample First Programs ASCII. Characteristics Basic Stamp 2 the controller in the Boe Bot

Transcription

1 Microcontrollers What is a Microcontroller Characteristics Basic Stamp 2 the controller in the Boe Bot Setting up Developmental Software Hardware Sample First Programs ASCII DEBUG using ASCII

2 What is a Microcontroller Characteristics How many microcontrollers did you use today? They are embedded in many common What else?? devices we use every day Some other examples: Handheld games Digital watches???????????????????? How do microcontrollers differ from PC μprocessors μprocessors use external circuitry to interface to non-computer devices (aka, Input/Output I/O devices)

3 What is a Microcontroller Characteristics How do microcontrollers differ from PC μprocessors (μp) Microcontrollers have circuitry to interface and control noncomputer devices The heart of both is a small computer on a chip Major Components Every system based upon a μp or microcontroller contains at least: Arithmetic Logic Unit (ALU) On Microcontroller Memory Unit- Some or all on the Microcontroller Control Unit On Microcontroller Input Unit On Microcontroller Output Unit On Microcontroller

4 Micro Controller Focused View of a Typical System Block Diagram

5 What is a Microcontroller Characteristics Major Components Interconnection of these is shown on the previous slide Arrows indicate direction of data, info, and control signal flow Large arrows indicate data or information flow Smaller arrows indicate the flow of control signals Logic Unit (ALU) On Microcontroller Area of the machine that performs Arithmetic operations and logical operations Memory Unit The memory stores information in groups called bytes The stored bytes can contain instructions (program) of the µc or data Input Unit Consists of all the devices that collect/take eternal information for input to the system

6 What is a Microcontroller Characteristics Major Components Shares pins with Output Output Unit Consists of all the devices that are used to transfer information from the system to the outside Shares pins with Input Basic Stamp 2 the controller module in this class First Basic Stamp module was introduced in 1992 Over 3 million sold The Stamp 2 is a later model than the on introduced in 1992 Basic Module components Micro controller chip (PIC16C57 on Basic Stamp 2) Internal memory (RAM and EEPROM)

7 What is a Microcontroller Basic Stamp 2 Basic Module components 5 volt regulator TTL levels 0 5V Set of basic commands Math I/O port control Programming Simplified custom version of BASIC PBASIC Speed 4000 PBASIC instructions per second

8 Basic Stamp 2 Pin-outs Pins 1-24 Critical Items What is a Microcontroller Sink/ Source limits on pins 5-20 VDD on pin 21 Pin 24 V IN limits System ground on Pin 23

9 What is a Microcontroller Basic Stamp 2 Embedded Computer Systems Modules such as the BASIC Stamp 2 are correctly called this Sometimes just Embedded System However, they are most commonly called microcontrollers Carrier Board used to hold the BASIC Stamp 2 on the Boe Bot

10 Overview of Microcontroller LAB Key Aspects Software Hardware Software Setup BASIC Stamp Editor You will use it on most of the Hand-On parts of the course Characteristics Aids the writing of PBASIC programs to control the Boe Bot Allows simple downloading of these programs to the Boe Bot It can them run autonomously Also displays messages sent from the Boe Bot

11 Getting Setup for the Course Software Setup BASIC Stamp Editor Characteristics Free from Parallax for use with their products Should be installed on your computer w/desktop Icon Click on it and open it Desktop Icon

12 First Programs Overview The BASIC Stamp and computer Communicate over the connecting USB or Serial cable Stream of ones and zeros flow each way First Program The following program is shown in BASIC Stamp Editor

13 First Programs First Program Program continued Some lines are typed and some are entered by selecting a button Clicking on this button will automatically place '{$STAMP BS2} at the beginning of your program. Clicking on this button will automatically place '{$PBASIC 2.5} at the beginning of your program. After entering the program Save it Select File then Save

14 First Programs First Program Program continued How thee program works First 2 lines are comments For human reading Note the apostrophe The net two lines are comments and Complier directives The DEBUG command tells the Stamp to send the message Formatters Code word that changes how a Stamp message is displayed DEC causes the display of a decimal value Control Characters CR causes a Carriage return on the line below the characters that are before it in the message

15 ASCII American Standard Code for Information Interchange Most microcontrollers and μps use this code to represent each keyboard character and function ASCII codes represent printed characters and symbols ASCII codes below 32 correspond to different functions or are spare Some of the functions are: cursor up, down, right, left, etc space Delete Etc. Machine and human versions of the codes Letter a ASCII code is 61 in machine readable form Reference page :

16 ASCII Bits and Bytes Most microcontrollers and μps smallest unit of memory used is a Byte A Byte consists of 8 bits A Bit is the smallest unit of information Each bit is either on or off (Logic 1 or 0) ASCII only use 7 of the 8 bits in a Byte ASCII only use 7 of the 8 bits in a Byte DEBUG using ASCII Sample Program

17 DEBUG using ASCII How it works ASCII Each letter in the DEBUG command corresponds to one ASCII code symbol that appeared in the Debug Terminal. DEBUG 66,65,83,73,67,32,83,116,97,109,112,32,50 66 is the ASCII code for capital B, 65 is the code for capital A and so on. 32 is the code for a space between characters. Notice that each code number was separated with a comma. The commas allow the one instance of DEBUG to execute each symbol as a separate command. This is much easier to type than 12 separate DEBUG commands.