Serial communication on pins TX/RX uses TTL logic levels (5V or 3.3V depending on the board). Free construction software for estimating. Don’t connect these pins directly to an RS232 serial port; they operate at +/- 12V and can damage your Arduino board.
Inter-integrated Circuit pronounced I-squared-C (I²C) or I2C is a two wire bus technology (well actually 4 wires because you also need the VCC and Ground) that is used for communication between multiple processors and sensors.
The two wires are:
* SDA - Serial Data (data line) and
* SCL - Serial Clock (clock line)
Remember, both these lines are 'synchronous' 'bidirectional' 'open-drain' and are 'pulled-up with resistors'.
The I2C bus technology was originally designed by Philips Semiconductors in the early ’80s to allow easy communication between components which reside on the same circuit board.
With I2C, you can connect multiple slaves to a single master (like SPI) or you can have multiple masters controlling single, or multiple slaves. Both masters and slaves can transmit and receive data. So, a device on I2C bus can be in one of these four states:
* Master transmit – master node is sending data to a slave
* Master receive – master node is receiving data from a slave
* Slave transmit – slave node is sending data to the master
* Slave receive – slave node is receiving data from the master
I2C is a 'short distance' 'serial communication protocol', so data is transferred 'bit-by-bit' along the single wire or the SDA line. The output of bits is synchronized to the sampling of bits by a clock signal 'shared' between the master and the slave. The clock signal is always controlled by the master. The Master generates the clock and initiates communication with slaves.
So, to sum it up>
Serial Port Multiplexer Arduino Free
Number of Wires used: 2
Serial Port Multiplexer Arduino
Synchronous or Asynchronous: Synchronous
Serial or Parallel: Serial
Clock Signal controlled by: Master Node
Voltages used: +5 V or +3.3 V
Maximum number of Masters: Unlimited
Maximum number of Slaves: 1008
Maximum Speed: Standard Mode = 100kbps
Fast Mode = 400kbps
High Speed Mode = 3.4 Mbps
Ultra Fast Mode = 5 Mbps