76
F. Firouzi et al.
DO0
DO1
DO2
DO3
DO4
DO5
DO6
DO7
DI0
DI1
DI2
DI3
DI4
DI5
DI6
DI7
Transmitter
Receiver
1
1
0
1
0
0
0
0
Parallel
Serial
SDO
Transmitter
Receiver
0 0 0 1 1 0 0 1
SDI
Fig. 2.17 Parallel and serial communication
2.5.3.4 Parallel Interfaces vs Serial Interfaces
Circuits rely on communication protocols to be able to exchange data among
themselves. While there are hundreds of communication protocols to support the
exchange of data, they can all be classified into two categories – serial or parallel
(see Fig. 2.17).
Parallel interfaces move many bits simultaneously and generally need data buses
with a size of 8, 16, or more bits. In contrast, serial interfaces stream data one bit
at a time, thereby it can function with only 1 wire, and generally do not use more
than 4 wires. Serial interfaces can also be categorized into two groups, namely,
synchronous and asynchronous [10].
• Synchronous: Synchronous serial interfaces match data line(s) to a clock signal so
that all devices share a mutual clock on the synchronous serial bus. This results
in an uncomplicated, quick, serial transfer; however, it also means at least one
additional wire is needed to connect communicating devices. SPI and I 2 C are
two common synchronous serial communication interfaces.
• Asynchronous: An asynchronous interface exchange data without the aid of an
external clock signal, which reduces the number of wires and I/O pins needed.
However, guarantee the reliability of data transmitting/receiving needs extra
effort. A universal asynchronous receiver/transmitter (UART) is an example of a
synchronous interface.
2.5.3.5 Universal Asynchronous Receiver/Transmitter (UART)
UART systems support reliable, reasonably speedy, full-duplex (two-way) communication using three signals: Rx (received serial data), Tx (transmitted serial data),
and a ground. Note that the Tx of one device should be linked to the Rx of the other
device and vice versa. Note that UART does not need a clock signal because it is
asynchronous (see Fig. 2.18) [11].
F. Firouzi et al.
DO0
DO1
DO2
DO3
DO4
DO5
DO6
DO7
DI0
DI1
DI2
DI3
DI4
DI5
DI6
DI7
Transmitter
Receiver
1
1
0
1
0
0
0
0
Parallel
Serial
SDO
Transmitter
Receiver
0 0 0 1 1 0 0 1
SDI
Fig. 2.17 Parallel and serial communication
2.5.3.4 Parallel Interfaces vs Serial Interfaces
Circuits rely on communication protocols to be able to exchange data among
themselves. While there are hundreds of communication protocols to support the
exchange of data, they can all be classified into two categories – serial or parallel
(see Fig. 2.17).
Parallel interfaces move many bits simultaneously and generally need data buses
with a size of 8, 16, or more bits. In contrast, serial interfaces stream data one bit
at a time, thereby it can function with only 1 wire, and generally do not use more
than 4 wires. Serial interfaces can also be categorized into two groups, namely,
synchronous and asynchronous [10].
• Synchronous: Synchronous serial interfaces match data line(s) to a clock signal so
that all devices share a mutual clock on the synchronous serial bus. This results
in an uncomplicated, quick, serial transfer; however, it also means at least one
additional wire is needed to connect communicating devices. SPI and I 2 C are
two common synchronous serial communication interfaces.
• Asynchronous: An asynchronous interface exchange data without the aid of an
external clock signal, which reduces the number of wires and I/O pins needed.
However, guarantee the reliability of data transmitting/receiving needs extra
effort. A universal asynchronous receiver/transmitter (UART) is an example of a
synchronous interface.
2.5.3.5 Universal Asynchronous Receiver/Transmitter (UART)
UART systems support reliable, reasonably speedy, full-duplex (two-way) communication using three signals: Rx (received serial data), Tx (transmitted serial data),
and a ground. Note that the Tx of one device should be linked to the Rx of the other
device and vice versa. Note that UART does not need a clock signal because it is
asynchronous (see Fig. 2.18) [11].