BASIC stamp manual v2.2

REVERSE – BASIC Stamp Command Reference

Page 378 • BASIC Stamp Syntax and Reference Manual 2.2 • www.parallax.com

Demo Program (REVERSE.bs1)

' REVERSE.bs1

' Connect the circuit shown in the REVERSE command description to I/O pin

' 0 and run this program. The LED will alternate between two states, dim

' and bright. The BASIC Stamp is using the REVERSE command to toggling I/O

' pin 0 between input and output states. When pin 0 is an input, current

' flows through R1, through the LED, through R2 to ground. Pin 0 is

' effectively disconnected and doesn't play a part in the circuit. The

' total resistance encountered by current flowing through the LED is R1 +

' R2 = 1220 ohms. When pin 0 is reversed to an output, current flows

' through R1, through the LED, and into pin 0 to ground (because of the 0

' written to PIN0). The total resistance encountered by current flowing

' through the LED is R1,220 ohms. With only 20% of the resistance, the LED

' glows brighter.

' {$STAMP BS1}

' {$PBASIC 1.0}

Setup:

PIN0 = 0 ' Put a low in the pin 0

' output driver

Main:

PAUSE 250 ' 1/4th second pause

REVERSE 0 ' reverse pin 0 I/O direction

GOTO Main ' do forever

Demo Program (REVERSE.bs2)

' REVERSE.bs2