Parallax BASIC Stamp 2e, Programming Manual

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5: BASIC Stamp Command Reference – OWIN
BASIC Stamp Programming Manual 2.0c
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Page 197
OWIN
BS1 BS2 BS2e BS2sx BS2p
OWIN Pin, Mode, [InputData]
Function
Receive data from a device using the 1-wire protocol.
•
Pin
is a variable/constant/expression (0 – 15) that specifies which
I/O pin to use. 1-wire devices require only one I/O pin (called DQ)
to communicate. This I/O pin will be toggled between output and
input mode during the OWIN command and will be set to input
mode by the end of the OWIN command.
•
Mode
is a variable/constant/expression (0 – 15) indicating the mode
of data transfer. The Mode argument controls placement of reset
pulses (and detection of presence pulses) as well as byte vs. bit input
and normal vs. high speed. See explanation below.
• InputData is a list of variables and modifiers that tells OWIN what to
do with incoming data. OWIN can store data in a variable or array,
interpret numeric text (decimal, binary, or hex) and store the
corresponding value in a variable, wait for a fixed or variable
sequence of bytes, or ignore a specified number of bytes. These
actions can be combined in any order in the InputData list.
Quick Facts
BS2p
Receive Rate Approximately 20 kbits/sec (low speed, not including reset pulse)
Special notes The DQ pin (specified by Pin) must have a 4.7 K
Ω
pull-up resister.
Explanation
The 1-wire protocol is a form of asynchronous serial communication
developed by Dallas Semiconductor. It only requires one I/O pin and that
pin can be shared between multiple 1-wire devices. The OWIN command
allows the BASIC Stamp to receive data from a 1-wire device.
The following is an example of the OWIN command:
Result VAR BYTE
OWIN 0, 1, [Result]
This code will transmit a "reset" pulse to a 1-wire device (connected to I/O
pin 0) and then will detect the device's "presence" pulse and then receive
one byte and store it in the variable Result.
Table 5.43: OWIN Quick Facts.
p
2
A
SIMPLE
OWIN
EXAMPLE
.