BASIC stamp manual v2.2
5: BASIC Stamp Command Reference – REVERSE
BASIC Stamp Syntax and Reference Manual 2.2 • www.parallax.com • Page 377
REVERSE
BS1 BS2 BS2e BS2sx BS2p BS2pe BS2px
REVERSE Pin
Function
Reverse the data direction of the specified pin.
• Pin is a variable/constant/expression (0 – 15) that specifies the I/O
pin to use. This pin will be placed into the mode opposite its current
input/output mode.
Quick Facts
Table 5.90: REVERSE Quick
Facts.
BS1 and all BS2 models
Related
Commands
INPUT and OUTPUT
Explanation
REVERSE is a convenient way to switch the I/O direction of a pin. If the
pin is an input, REVERSE makes it an output; if it’s an output, REVERSE
makes it an input.
Remember that “input” really has two meanings: (1) Setting a pin to input
makes it possible to check the state (1 or 0) of external circuitry connected
to that pin. The current state is in the corresponding bit of the INS register
(PINS on the BS1). (2) Setting a pin to input also disconnects the output
driver, the corresponding bit of OUTS (PINS on the BS1).
The demo program below illustrates this second fact with a two-tone LED
blinker.
Figure 5.35: LED Circuit for Demo
Programs.
R1
R2
220
LED
NOTE: Expressions are not allowed as
arguments on the BS1. The range of
the Pin argument on the BS1 is 0 – 7.
1
A
ll
2
1