CP480 Wireless Communication and Networks lab
Universal Asynchronous Receiver Transmitter (UART)
This week's laboratory investigates
(or EIA 232) communication.
The RS-232 protocol has been around since 1962. Originally designed
to basically connect a single "smart" device to a single "dumb"
device, it is now still very commonly used to connect sensors to
microprocessors or microcontrollers, and so will remain relevant for
the forseable future. It's also one of the simplest serial protocols,
and so it's easy to study.
The Arduino board has a UART built-in, so it can be used to study
Note: The UART pins on the Arduino will be at
TTL levels, not at acceptable RS-232 levels.
- Become familiar with the hardware layer of a UART.
- Arduino Uno board, with LCD display
Demonstrate and explain your results to the
- Look at a
simple Arduino serial communication example.
Note: The Arduino uses the serial port internally, so
while you are programming you can't have the pins tied to each
other or some other device. Only make those connections after you
have finished uploading.
(A later exercise will show you how to solve this problem.)
Connect the Tx and Rx pins of your Arduino so it communicates
with itself. Write a sketch to send a character every second and
display received characters on the LCD.
Hint: Start with
the simple example and modify it
to repeatedly send a character
out from the UART.
Show your pin assignments on the diagram.
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