Parallax BASIC Stamp 2e Programming Manual page 270

REVERSE - BASIC Stamp Command Reference
Demo Program (REVERSE.bas)
' 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 = 440 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 half the resistance, the LED glows brighter.
'{$STAMP BS1}
PIN0 = 0 ' Put a low in the pin 0 output driver.
Again:
PAUSE 200 ' Brief (1/5th second) pause.
REVERSE 0 ' Invert pin 0 I/O direction.
GOTO Again ' Repeat forever.
Demo Program (REVERSE.bs2)
' Connect the circuit shown in the REVERSE command description to I/O pin 0 and run this
' program. The LED will alternate between two states, dim and bright. The BASIC Stamp is
' using the REVERSE command to toggling I/O pin 0 between input and output states. When
' pin 0 is an input, current flows through R1, through the LED, through R2 to ground. Pin 0 is
' effectively disconnected and doesn't play a part in the circuit. The total resistance
' encountered by current flowing through the LED is R1 + R2 = 440 Ohms. When pin 0 is
' reversed to an output, current flows through R1, through the LED, and into pin 0 to ground
' (because of the 0 written to OUT0). The total resistance encountered by current flowing
' through the LED is R1, 220 Ohms. With only half the resistance, the LED glows brighter.
'{$STAMP BS2}
OUT0 = 0 ' Put a low in the pin 0 output driver.
Again:
PAUSE 200 ' Brief (1/5th second) pause.
REVERSE 0 ' Invert pin 0 I/O direction.
GOTO Again ' Repeat forever.
Page 268 • BASIC Stamp Programming Manual 2.0b • www.parallaxinc.com
'STAMP directive (specifies a BS1)
'STAMP directive (specifies a BS2)
1
2 2 2
2
e p
sx
NOTE: This is written for the BS2
but can be used for the BS2e,
BS2sx and BS2p also. Locate the
proper source code file or modify
the STAMP directive before
downloading to the BS2e, BS2sx or
BS2p.