Basic StampOEM module

By Wilmer Arellano

OEM BASIC Stamp 2sx Wiring diagram

Note:

- is connection to negative pole of the battery

22

0 O

hm

22

0 O

hm

22

0 O

hm

22

0 O

hm

Pushbutton

Buzzer

LED

LED LED

OUT

PIRMotionsensor

9 V battery

CO

M p

ort

Mic

rocon

troller

ch

ip

15

KO

hm

' {$STAMP BS2}' {$PBASIC 2.5}OUTPUT 4 'PIN 4 Declared as outputINPUT 0 'PIN 0 Declared as inputGreen:OUT4=IN0 'PIN 4 will take the value of PIN 0 (switch)PAUSE 1000GOTO Green

Turn ON LED with Switch Input Output Declarations

Variables

Bit 0 or 1 Nibble (Nib) 0-15 Byte 0-255 Word 0-65535 or -32768 to +

32767

' {$STAMP BS2}' {$PBASIC 2.5}NS VAR Bit 'NS is a Bit VariableEW VAR Bit 'EW is a Bit VariableTOTAL VAR Byte 'TOTAL is a Byte VariableNOC CON 20 'NOC is a constantTOTAL = 0OUTPUT 4INPUT 1TOTAL = TOTAL +100DEBUG ? TOTALTOTAL= TOTAL/3DEBUG ? TOTALDEBUG ? NOC

Arithmetic Example

Pseudo Code

Start of program Measure temperature

Temperature < 100 F? Yes, Turn on heat

Temperature > 102 F? Yes, Turn on cooling fan Go back to start.

7

Start

MeasureTemperature

Temp.< 100

EnergizeHeater

Temp.> 102

EnergizeFan

Start

Yes

No

Yes

No

Flowchart

8

Sequential Flow Example

Pseudo-Code:

Start of program Turn off LED 1 Turn off LED 2 Pause for 2 seconds Light LED 1 Pause for 2 seconds Light LED 2

End of program

Flowchart:Flowchart:

' {$STAMP BS2}' {$PBASIC 2.5}LED_OFF CON 0 'LED_OFF is a constant of value 0LED_ON CON 1 'LED_ON is a constant of value 1start:OUTPUT 4OUTPUT 15OUT4 =LED_OFFOUT15 =LED_OFFPAUSE 1000OUT4 =LED_ONOUT15 =LED_ONPAUSE 1000GOTO start

Code:Code:

Start

Turn OFF LED1

Turn OFF LED2

2 Second Pause

Turn ON LED1

Turn ON LED2

2 Second Pause

End

Branching Overview - GOTO Branching is the act of breaking out of a

sequence to perform code in another location of the program.

The simplest form of branching is to use the GOTO instruction: GOTO label

' {$STAMP BS2}' {$PBASIC 2.5}OUTPUT 4 'PIN 4 Declared as outputINPUT 0 'PIN 0 Declared as inputGreen:OUT4=IN0 'PIN 4 will take the value of PIN 0 (switch)PAUSE 1000GOTO Green

Conditionals Overview

The previous example is an unconditional branch; the program will branch back to Main regardless of any code parameters.

In a conditional branch a decision is made based on a current condition to branch or not to branch.

As humans, we constantly make decisions based on input as to what to perform. Shower too cold? Turn up the hot. Shower too hot? Turn down the hot water.

Microcontrollers can be programmed to act based on conditions

IF…THEN

The IF-THEN is the primary means of conditional branching.IF condition THEN addressLabel

If the condition is evaluated to be true, execution will branch to the named address label.

If the condition is not true, execution will continue to the next step in the program sequence.

A condition is typically an equality:value1 = value2value1 > value2value1 < value2IN8 = 1

12

IF-THEN Example: Alarm This program will sound the alarm as long as pushbutton 1 is pressed.

Start: Start: • Is button 1 pressed? Is button 1 pressed? • Yes, Go sound Alarm Yes, Go sound Alarm • No, Go back to start No, Go back to start Alarm Alarm • Sound speaker Sound speaker • Go back to start of programGo back to start of program

' {$STAMP BS2}' {$PBASIC 2.5}SWITCH VAR Bitstart:SWITCH=IN0IF SWITCH=1 THEN buzz 'IF switch is pressed then turn on buzzerGOTO startbuzz:FREQOUT 1, 1000, 5000GOTO start

Pseudo-Code Flowchart

Program Code

Button 1Pressed

Main

Speaker2000Hz for1 second

Main

TrueFalse

' {$STAMP BS2}' {$PBASIC 2.5}NS VAR BitEW VAR BitOUTPUT 4OUTPUT 10INPUT 1Green:OUT4=1OUT10=0NS=IN1IF NS=1 THEN greenOUT4=0OUT10=1PAUSE 10000GOTO Green

What does this program do?